Hp-Ib Interface - HP 9000 Series 310 Service Information Manual

RS-232
An RS-232 Interface section is part of the processor board's electronics. Using an INS8250
UART, it's almost identical to the HP 98644A RS-232 Serial Interface Card. The processor
board's RS-232 differs from the HP 98644A Interface Card in that it:
• Allows interrupts at level 5 only. There are no switches to change the interrupt level is
the same as the HP 98644 Card.
• Permanently sets the select code to 9. The HP 98644 card has switches which allow this
address to be changed.
• Does not allow reconfiguration to change the RS-232's ID to that of the HP 98626 card.
Two switches on the 98561-66511 board are associated with RS-232. They perform the following
functions:
• Controls the local/remote bit in the ID register.
• Sets the handshake input lines to their default condition, all ones.
In addition to the registers built into the INS8250 UART, two external register have also been
implemented. Both sets of registers are multi-mapped within a 64 K-byte region of memory
associated with I/O select code 9.
HP-IB Interface
Hewlett-Packard Interface Bus (HP-IB) is HP's version of the IEEE 488 interface standard.
HP-IB on this processor board is much like HP-IB implementations on other HP 9000 Series
200 computers. It uses a TMS9914 HP-IB controller which allows data transfer rates up to
450 K-bytes/second. The TMS9914 is a memory-mapped I/O device which is multiple-mapped
within a 64 K-byte internal I/O device.
Two registers control hardware which can generate an interrupt as a result of a HP-IB device
responding to a parallel poll. It has the ability to generate an interrupt from a parallel poll
response. For this feature, two registers external to the TMS9914 are used. These registers are
in addition to the two external registers that exist for internal HP-IB interfaces in other Series
200 computers.
All registers associated with the HP-IB are multiple Inapped within a 64 K-byte block of memory
in the internal I/O address range.
Information on the TMA9914A and its registers can be found in the 'TMS9914A General Purpose
Interface Bus (GPIB) Controller' Data Manual.
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Functional Description