3 comm port status2 register, 4 comm port status3 register – Sundance SMT329 User Manual

Page 33

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Rxalfull

Receive fifo almost full (has 128 empty entries)

Rxemp

Receive fifo is empty

Rxfull

Receive fifo is full

Rxrderr

Receive fifo read while fifo empty

Rxwrerr

Receive fifo write while fifo full

Txalemp

Transmit fifo almost empty (has 128 entries left)

Txalfull

Transmit fifo almost full (has 128 empty entries)

Txemp

Transmit fifo is empty

Txfull

Transmit fifo is full

Txrderr

Transmit fifo read while fifo empty

Txwrerr

Transmit fifo write while fifo full


The receive fifo not empty bit (-Rxemp) becomes set when a receive word is in the comm port
data receive fifo. When all the comm port data in the receive fifo is read, this bit is reset.
When the transmit fifo not full bit (-Txfull) is set, it indicates that the VME host can write a
new 32 bit word to the comm port data register for later transmission to the comm port.

4.5.1.3 Comm Port Status2 register


The status2 register is accessible by the VME host at address
IO base + 0x94-0x97. The bit definitions for this register are:

31-28 30-16

15-12

28

Rxrdcount

Rxwrcount

R, 0000

R, 0

R, 0000

R, 0


Bit Mnemonic

Description

Rxrdcount

Receive fifo read pointer

Rxwrcount

Receive fifo write pointer


This status register is intended for diagnostic use only.

4.5.1.4 Comm Port Status3 register

User Manual SMT329

Page 33 of 52 Last

Edited:

09/02/2007

10:58:00

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