8 fifo_cr: fifo almost empty/full register – ADLINK PCI-7300A User Manual
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• Registers
3.8 FIFO_CR: FIFO almost empty/full register
The register is used to control the FIFO programmable almost empty/full flag. 
Address: BASE + 0x018 
Attribute: WRITE Only 
 
Data Format: 
Bits
7
6
5
4
3
2
1
0
Bit 15~0
PB_PAE_PAF
Bit 31_16
PA_PAE_PAF
PB_PAE_PAF (WO) 
Programmable almost empty/full threshold of PORTB FIFO, 2 
consecutive writes are required to program PORTB FIFO. 
Programmable almost empty threshold first. 
PA_PAE_PAF(WO)
Programmable almost empty/full threshold of PORTA FIFO, 2 
consecutive writes are required to program PORTA FIFO. 
Programmable almost empty threshold first. 
3.9 POL_CNTRL: Control Signal Polarity Control
Register
The register is used to control the control signals’ polarity. The control signals 
include DI_REQ, DI_ACK, DI_TRG, DO_REQ, DO_ACK and DO_TRG. 
Please note that this register is for PCI-7300A Rev.B and cPCI-7300 only. 
Address: BASE + 0x1C 
Attribute: READ/WRITE 
 
Data Format: 
Bit # 3~0
DO_REG_NEG
DI_TRG_NEG
DI_ACK_NEG
DI_REQ_NEG
Bit # 71~4
-
-
DO_TRG_NEG
DO_ACK_NEG
Bit # 31~8
Don’t Cared
DI_REQ_NEQ (R/W)
0: DI_REQ is rising edge active 
1: DI_REQ is falling edge active