HP Series 80 PRM-85
PRM-85 - User Guide
As the PRM-85 is supplied as a PCB with bare chips, please ensure basic protection against electro-static discharges (ESD) that may damage it. For example, place the board on the conductive plastic bag it came in when changing EPROMs.
Below are quick set-up guides for the HP-85A (with and without EMS support), the HP-85B and the HP-86/87.
Quick set-up for HP-85A (without EMS support)
The PRM-85 is supplied with SuperROM85 V1, a 27512 EPROM containing 8 HP-85 ROM images in socket U2. Set the links as follows on the jumper block for U2 (new boards are normally supplied with these jumpers in place):
Jumper
Contacts ROM Name
-------- ---------------------
9 to 17 Advanced Programming
10 to 18 Assembler
11 to 19 Service-85
12 to 20 Program Development
13 to 21 Mass Storage
14 to 22 Matrix
15 to 23 Input/Output
16 to 24 Extended Mass Storage
nb - The EMS ROM was not designed to work on the HP-85A, in particular it does not work with the HP-85A version of the Mass Storage ROM. See next section if you require EMS support.
Please ensure you do not enable a ROM image on the PRM-85 and have the same ROM plugged into your machine at the same time. If you are unsure what ROMs your machine has, just enable the Assembler ROM image and run some checks using the MEM command to determine what ROMs are present.
For a ROM image on a 2764 EPROM, use socket U1, and connect pins 8 and 16 on the jumper block for U1 (see jumper block settings). Set SW1 to the ROM number required.
Power-off the Series 80 machine and plug the PRM-85 board into one of the expansion sockets at the rear (component side upwards). Power-up and check that the new ROM(s) have been enabled.
Quick set-up for HP-85A (with EMS support)
To provide EMS support, the PRM-85 requires the SuperROM85 V2, available here - 85SUPRM2.ZIP (105KB). Burn this file to a 27512 EPROM, and place this SuperROM in socket U2. This includes versions of the Mass Storage and EDISK ROMs that were built into the HP-85B. These are needed by the EMS ROM. This file excludes the Program Development ROM.
Of these 8 ROM images, 7 are set using the same pre-set addresses as for the HP-85 SuperROM V1, and EDISK uses address 209 set on the DIL switch SW2.
Set the links as follows on the jumper block for U2:
Jumper
Contacts ROM Name
-------- ---------------------
9 to 17 Advanced Programming
10 to 18 Assembler
11 to 19 Service-85
4 to 12 EDISK (85B version)
13 to 21 Mass Storage (85B version)
14 to 22 Matrix
15 to 23 Input/Output
16 to 24 Extended Mass Storage
NB The only difference above from the default is that the jumper that was between contacts 12 and 20 is now set between 4 and 12.
Set DIL switch SW2 for the EDISK ROM:
ROM Name
Number Switch settings
------------------- ------ ---------------
EDISK
209 11010001
The switch settings are shown in the order 8 (on the left) to 1 (on the
right).
Please ensure you do not enable a ROM image on the PRM-85 and have the same ROM plugged into your machine at the same time. If you are unsure what ROMs your machine has, just enable the Assembler ROM image and run some checks using the MEM command to determine what ROMs are present.
For a ROM image on a 2764 EPROM, use socket U1, and connect pins 8 and 16 on the jumper block for U1 (see jumper block settings). Set SW1 to the ROM number required.
Power-off the Series 80 machine and plug the PRM-85 board into one of the expansion sockets at the rear (component side upwards). Power-up and check that the new ROM(s) have been enabled.
Quick set-up for HP-85B
Follow the instructions for the HP-85A, but change the jumper contacts for U2 as follows. This is because the HP-85B has built in Mass Storage and Input/Out ROMs, as well as the EDISK ROM.
Jumper
Contacts ROM Name
-------- ---------------------
9 to 17 Advanced Programming
10 to 18 Assembler
11 to 19 Service-85
12 to 20 Program Development
14 to 22 Matrix
16 to 24 Extended Mass Storage
So remove links from 13 to 21 and from 15 to 23.
Quick set-up for HP-86 / HP-87
An optional 27512 EPROM containing 8 HP-87 ROM images is available, or download 87SUPER.ZIP (74KB) containing the images then burn them into a blank EPROM. Place this SuperROM in socket U2.
Of these 8 ROM images, 5 are set using the same pre-set addresses as for the HP-85 SuperROM, and the remaining 3 use addresses set on the 2 DIL switches. If the DIL switch associated with the U1 jumper block is used to access the SuperROM, then the ROM in U2 can't be accessed.
Set the links as follows on the jumper block for U2:
Jumper
Contacts ROM Name
-------- ---------------------
9 to 17 Advanced Programming
10 to 18 Assembler
14 to 22 Matrix
15 to 23 Input/Output
16 to 24 Extended Mass Storage
There are three other images on the SuperROM, for the Advanced Programming 2, Matrix 2 and Plotter ROMs. These use the following jumpers on the jumper block for U2:
Jumper
Contact ROM Name
------- ----------------------
11 Advanced Programming 2
12 Matrix 2
13 Plotter
The switch SW2 sets the address on contacts 1 to 8 of jumper block for U2, and SW1 sets the address on contacts 1 to 8 of jumper block for U1. The 8 contacts are connected together, so the most convenient contact should be used.
The following shows the switch settings for the above three ROMs:
ROM Name
Number Switch settings
---------------------- ------ ---------------
Advanced Programming 2 231 11100111
Matrix 2
177 10110001
Plotter
240 11110000
The switch settings are shown in the order 8 (on the left) to 1 (on the right).
For example, to enable Advanced Programming 2 set switch SW2 to 11100111 and add a jumper from contacts 11 to 3 on jumper block 2.
To enable Matrix 2 as well, set switch SW1 to 10110001 and use a jumper wire between contact 12 on jumper block 2 and pin 1 (ie the nearest) on jumper block 1. If using a jumper from block 1 to block 2 then don't connect any jumpers to pins 9 to 16 on jumper block 1, as this would cause a clash.
Please ensure you do not enable a ROM image on the PRM-85 and have the same ROM plugged into your machine at the same time. If you are unsure what ROMs your machine has, just enable the Assembler ROM image and run some checks using the MEM command to determine what ROMs are present
The HP-87 has no built in ROMs, but some of the other machines such as the HP-86B have several ROMs built in so please check first using the Assembler ROM.
If switch SW1 is not used to enable part of the HP-87 SuperROM, socket U1 can be used for a ROM image on a 2764 EPROM. Connect pins 8 and 16 on the jumper block for U1 (see jumper block settings). Set SW1 to the ROM number required.
Power-off the Series 80 machine and plug the PRM-85 board into one of the expansion sockets at the rear (component side upwards). Power-up and check that the new ROM(s) have been enabled.
General Description
The PRM-85 is an enhanced replacement for the HP 82929A Programmable ROM Drawer module. This module allows you to incorporate additional ROM software into the HP Series 80 computer system, increasing its ROM size and so extending its capabilities. EPROM (erasable programmable read-only-memory) chips that you have been pre-programmed fit into the drawer, which has two sockets each of which accommodate any EPROM from 8K byte (2764 device) to 64K byte (27512 device).
Typically the PRM-85 will be used with a 27512 'SuperROM' containing a mix of 8 commonly used and hard-to-find ROM images, leaving the other socket spare for either another ROM image or a user program.
- A layout of the PRM-85 is shown below:
+-------------------------------------------+
| |
| |
| +----+ +----+ |
| |1 | |1 | |
| | | | | |
| | U1 | | U2 | +------+ |
| | | | | | SW1 | |
| | | | | +------+ |
| | | | | |
| +----+ +----+ |
| |
| |
| +--+ JB2 |
| | | JUMPER |
| | | BLOCK +------+ |
| | | FOR U2 | SW2 | |
| | | ENABLE +------+ |
| +--+ |
| |
| +-+ JB1 |
| | | JUMPER |
| | | BLOCK |
| | | FOR U1 |
+-+ | | ENABLE +-+
| +-+ |
| |
| |
| |
| |
| |
| |
| |
++ ++
| |
+---+ +---+
| |
+-----------------------------+
U1 and U2 are 28 pin DIL sockets. SW1 and SW2 are 8 way DIP switches, whilst JB1 and JB2 are DIL pin headers.
The maximum number of HP-85 ROM images which can be stored for each EPROM
device type is given in this table:
| EPROM Device | EPROM Size (bytes) | Number of Images |
| 2764 | 8K | 1 |
| 27128 | 16K | 2 |
| 27256 | 32K | 4 |
| 27512 | 64K | 8 |
ROM Addressing
The HP Series 80 uses a scheme called ROM addressing to access any one of 255 8K ROMs using memory mapping. Each ROM has to have a different ROM address, at boot-up all available addresses are scanned and if a ROM is found (by checking the first two bytes of the ROM code) it is initialized and any keywords become usable.
ROM addresses can be set up using the DIP switches SW1 and SW2 (in a similar way to the original HP Programmable ROM module). These switches control the enable signal delivered to the jumper blocks for U1 (EPROM 1) and U2 (EPROM 2). This allows any address from 0 to 255 (Hex 00-FF) to be used to enable a ROM.
The switches follow the usual binary convention, so you will need to convert the ROM number to binary and set the switches as needed.
There are two switch types that have been used on the PRM-85.
On the blue rocker switches 'OFF' = 0 and 'ON' =1
On the black slide switches 'ON' = 0 and 'OFF'=1
On both types switch 8 is the most significant bit (27 = 128), and switch 1 is the least significant bit (20 = 1)
In addition to these two switchable decodes, there are 8 built-in decodes that are generated by the control circuitry on the PRM-85 that can be used as enables, see section on the SuperROM.
Jumper Block Settings
There are separate jumper blocks for each EPROM socket. Contact designations
for the U1 and U2 Jumper Blocks are shown below:
+--+--+
+--+--+--+
| 1| 9| | 1| 9|17|
+--+--+ +--+--+--+
| 2|10| | 2|10|18|
+--+--+ +--+--+--+
| 3|11| | 3|11|19|
+--+--+ +--+--+--+
| 4|12| | 4|12|20|
+--+--+ +--+--+--+
| 5|13| | 5|13|21|
+--+--+ +--+--+--+
| 6|14| | 6|14|22|
+--+--+ +--+--+--+
| 7|15| | 7|15|23|
+--+--+ +--+--+--+
| 8|16| | 8|16|24|
+--+--+ +--+--+--+
U1 Jumper Block U2 Jumper Block
(JB1)
(JB2)
Jumpers will be placed between contacts in these blocks to configure the enable lines for the EPROM devices. This is so that any 8K block within an EPROM can be selected.
The contacts on the jumper block for U1 and U2 are made up as follows:
Contacts 1 to 8: output from DIP switch for ROM address.
Contacts 9 to 16: input to EPROM address circuit.
Jumper block U2 has an additional column of contacts as follows:
Contacts 17 to 24: outputs from PRM-85 board for 8 pre-set ROM addresses.
Jumper links are placed from left to right so that a ROM address output (either from a DIP switch or preset) is connected to the correct address line on the EPROM. Alternatively a wire with plugs on each end can be used in place of a jumper.
Jumper contacts 1 through 8 are tied together on the module and carry an enable signal generated by the ROM address DIP switches for each EPROM. For example, if the DIP switch for U1 is set to Hex CF (decimal 207), contacts 1-8 on the U1 jumper block will generate an active low (logic '0') select signal when the HP-85 is addressing ROM CF. For all other ROM addresses this signal would be a logic '1'.
Jumper contacts 9 through 16 are the enable inputs to the EPROM address control circuitry. They control how each EPROM is enabled and what will be applied to EPROM address lines 15, 14, and 13. Contacts 9 through 16 on each Jumper Block are designated Enable 0 through Enable 7, respectively.
The Enable 0-7 lines are pulled up 'high' so when left unconnected they are inactive. Placing jumpers in the Jumper Blocks will connect these lines to either the enable generated by the DIP switch setting or to the built-in ROM decodes.
The table below shows how these enables are used by the control circuitry to generate the chip enable and address lines to the U1 and U2 EPROMs. Pins 13, 14 and 15 are used as address lines on EPROMs bigger than the 2764. See Chipdir for more info on EPROMs.
Active Generated
Enable Signal EPROM EPROM Address
(Jumper Contact #) Enabled 15 14 13
-------------------- ------- ---------
U1 Enable 0 (JB1-9) U1
0 0 0
U1 Enable 1 (JB1-10) U1
0 0 1
U1 Enable 2 (JB1-11) U1
0 1 0
U1 Enable 3 (JB1-12) U1
0 1 1
U1 Enable 4 (JB1-13) U1
1 0 0
U1 Enable 5 (JB1-14) U1
1 0 1
U1 Enable 6 (JB1-15) U1
1 1 0
U1 Enable 7 (JB1-16) U1
1 1 1
U2 Enable 0 (JB2-9) U2
0 0 0
U2 Enable 1 (JB2-10) U2
0 0 1
U2 Enable 2 (JB2-11) U2
0 1 0
U2 Enable 3 (JB2-12) U2
0 1 1
U2 Enable 4 (JB2-13) U2
1 0 0
U2 Enable 5 (JB2-14) U2
1 0 1
U2 Enable 6 (JB2-15) U2
1 1 0
U2 Enable 7 (JB2-16) U2
1 1 1
It is important to remember that when using EPROMs smaller than a 27512, the unused address lines MUST be tied high. For example, when using a 2764 device the only valid jumper connection would be to contact 16, since Addr 15,14,13 must all be high or logic '1'. For a 27128 device (which has address range of 0000H to 3FFFH), the jumper to contact 16 would enable the ROM image stored at EPROM starting address 2000H and the jumper to contact 15 would enable the ROM image stored at starting address 0000H. The table below lists the valid Enables and ROM image starting address for each EPROM device type, corresponding to which enable line (and hence jumper) is used for that address (XXXX shows an invalid address).
Active Enable ROM Image Start Address (Hex)
Signal (pin) 2764 27128 27256 27512
------------- ----- ----- ----- -----
Enable 0 (9) XXXX XXXX XXXX 0000
Enable 1 (10) XXXX XXXX XXXX 2000
Enable 2 (11) XXXX XXXX XXXX 4000
Enable 3 (12) XXXX XXXX XXXX 6000
Enable 4 (13) XXXX XXXX 0000 8000
Enable 5 (14) XXXX XXXX 2000 A000
Enable 6 (15) XXXX 0000 4000 C000
Enable 7 (16) 0000 2000 6000 E000
So for example using a 27512, use address contact 14 to access the 8K block starting at address
A000H.
Built-In ROM Decodes
The PRM-85 contains 8 built-in ROM decodes. This is like having 8 additional DIP switches preset to popular HP-85 ROM addresses. These decodes are available on Jumper Block 2, contacts 17 through 24. This makes it easy to enable images on U2 since the built-in decodes are located adjacent to the Enable 0-7 signals on Jumper Block 2. (Note that connections could also be made to the Jumper Block 1 Enables but this would require wire jumpers.) The built-in ROM addresses are shown below with their associated contact number:
Jumper JB2 Decoded
Contact# ROM Address ROM Name
---------- ------------ --------------------
17 232 (E8 Hex) Advanced Programming
18 40 (28 Hex) Assembler
19 224 (E0 Hex) Service-85
20 8 (08 Hex) Program
Development
21 208 (D0 Hex) Mass Storage
22 176 (B0 Hex) Matrix
23 192 (C0 Hex) Input/Output
24 207 (CF Hex) Extended Mass Storage
NB - These decodes are programmed into the Altera EPLD chip. Custom
decodes are also available, POA.
Setup for 27512 SuperROM85 V1 Device
The use of the built-in decodes allows multiple ROM images to be active simultaneously. As default the PRM-85 is supplied with a 27512 EPROM in socket U2 programmed with ROM images at the following addresses:
EPROM Address ROM# ROM Name
------------- ---- ---------------------
0000-1FFF 232 Advanced Programming
2000-3FFF 40 Assembler
4000-5FFF 224 Service-85
6000-7FFF 8 Program
Development
8000-9FFF 208 Mass Storage (85A version)
A000-BFFF 176 Matrix
C000-DFFF 192 Input/Output
E000-FFFF 207 Extended Mass Storage
Jumpers can then be placed in Jumper Block 2 at the following positions : 9-17,10-18,11-19,12-20,13-21,14-22,15-23,16-24. This will allow all the ROMs listed above to be active (along with an additional EPROM in U1.)
If a jumper lead is used from pin 9 of JB2 to an enable pin of JB1 then U1 can contain a 27128 or larger EPROM then 2 ROM images can be used giving a maximum of 10.
A hybrid ROM can be made by replacing any of the individual ROM images in a SuperROM with a different ROM image, which then would require the ROM address to be set using switches SW1 or SW2, and the appropriate jumper changed.
Example Setup for 2764 Devices
One or two 2764 EPROMs are supported, the same as the original HP module. For each EPROM socket (U1 or U2) set the appropriate DIP switch (SW1 or SW2) to the correct ROM address and place a wire jumper at position 8-16 of the appropriate Jumper Block (JB1 or JB2). This should be the only jumper present on that particular Jumper Block.
Place the EPROMs in the correct sockets (U1 or U2) and you are ready to go.
Note that this module does not support the use of 2732 devices. Any existing 2732 EPROMs will have to be reprogrammed into a 2764 (or larger) device.
Further info
See ROMs and EPROMs.
More ROM images are available from the Series 80 pages.
There is also a SYSEXT ROM for the HP-87.
Reference to the original Programmable ROM Module instructions.
This page was last revised on: 2/08/20