How do you determine a 71B memory-mapped I/O device address?
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03-31-2021, 07:35 AM
(This post was last modified: 03-31-2021 09:23 AM by J-F Garnier.)
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RE: How do you determine a 71B memory-mapped I/O device address?
Hi Mark,
(I'm curious of what you have in mind to ask such a question - I may have an idea :-) The soft-configuration MMIO address allocation is similar to memories. The MMIO are configured starting at 20000 and a system buffer is created to hold the configuration addresses and the MMIO class as reported by the C=ID opcode. Then, when an application (the HP-IL ROM for instance) wants to address a MMIO device it can manage, it scans the buffer to find a MMIO device of the corresponding class (HP-IL mailbox is device class 0). See the FNDMBX (find mailbox) routine in the HP-IL ROM. A list of the MMIO classes is defined here pages 7-8. BTW, I don't know what was the memory controller device, I thought it could be the device used in the HHP and CMT memory modules, but never found any evidence for it. So if you plan to create a soft-configured MMIO device, use a MMIO class different from 0 and 2, and get its assigned address from the configuration buffer by looking at your class id. Or, if you want to keep it simple, use a hard address like the card reader does, You can use the range 2C1xx-2CFxx for instance. Don't use any address in 2Dxxx, 2Exxx, 2Fxxx. J-F |
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Messages In This Thread |
How do you determine a 71B memory-mapped I/O device address? - mfleming - 03-30-2021, 11:57 PM
RE: How do you determine a 71B memory-mapped I/O device address? - Giuseppe Donnini - 03-31-2021, 12:21 AM
RE: How do you determine a 71B memory-mapped I/O device address? - rprosperi - 03-31-2021, 01:07 AM
RE: How do you determine a 71B memory-mapped I/O device address? - Giuseppe Donnini - 03-31-2021, 01:23 AM
RE: How do you determine a 71B memory-mapped I/O device address? - rprosperi - 03-31-2021, 01:31 AM
RE: How do you determine a 71B memory-mapped I/O device address? - Sylvain Cote - 03-31-2021, 02:28 AM
RE: How do you determine a 71B memory-mapped I/O device address? - mfleming - 03-31-2021, 04:55 AM
RE: How do you determine a 71B memory-mapped I/O device address? - J-F Garnier - 03-31-2021 07:35 AM
RE: How do you determine a 71B memory-mapped I/O device address? - mfleming - 03-31-2021, 04:39 PM
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