INDUSTRIAL I/O PACK SERIES AVME9675A
VME64x bus 6U CARRIER BOARD
Acromag, Inc. Tel: 248-295-0310
- 40 - http://www.acromag.com
- 40 -
https://www.acromag.com
The VME64x bus interface is implemented in the logic of the
carrier board’s
Field Programmable Gate-Array (FPGA). The FPGA implements VME64x bus
specification ANSI/VITA 1-1994 (VME64) & ANSI/VITA 1.1-1997 (VME64x) as
an interrupting slave including the following data transfer types.
*
A24, D16/D08(O) CR/CSR Register Space
*
A16, D16/D08(O) Carrier Register Short I/O Access
*
A16, D16/D08(O) IP Module ID Space
*
A16, D16/D08(EO) IP Module I/O Space
*
A24, D16/D08(EO) IP Module Memory Space
The carrier board’s VME64x bus data tra
nsfer rates are typically:
•
450ns for accesses to the carrier board registers.
•
450ns for data transfers to the IP modules (assuming 0 wait states on
IP).
The c
arrier board’s FPGA monitors the six geographical address signal inputs
supplied by the VME64x backplane on the P1 connector. These signals
determine the base address of the carrier in the standard (A24)
Configuration ROM / Control & Status Register (CR/CSR) address space. The
host computer must scan the CR/CSR space to determine active card
locations within the VME64x chassis. When the CR/CSR address matches
the card’s, the FPGA controls and implements the required bus transfer
allowing communication wi
th the card’s CR/CSR space.
4.3 Carrier Board Registers
The carrier board registers (presented in section 3) are implemented in the
logic of the carrier board’s FPGA. An outline of the functions provided by
the carrier board registers includes:
•
Configuration ROM (CR within CR/CSR space)
registers provide carrier
board identification and capabilities information.
•
Control & Status Registers (CSR within CR/CSR space)
allow the base
address of the Short (A16) I/O carrier space to be relocated on 1K byte
boundaries as desired by the host computer using the
Function 0
Address DEcoder CompaRe (ADER)
register and accesses to this space
to be enabled or disabled using the
Bit Set or Bit Clear Registers
.