Manual

Description of the data path
GUPPY Technical Manual V7.1.0
165
To read data:
1. Query RDRD flag (buffer ready?) and write the number of bytes the host
wants to read to RBUF_CNT.
2. Read the number of bytes pending in the receive buffer RBUF_ST (more
data in the buffer than the host wanted to read?) and the number of
bytes left for reading from the receive FIFO in RBUF_CNT (the host
wanted to read more data than were in the buffer?).
3. Read received characters from SIO_DATA_REGISTER, beginning at char 0.
4. To input more characters, repeat from step 1.
008h RECEIVE_BUFFER_STAT
US_CONTRL
RBUF_ST [0..7] SIO receive buffer status
RD: Number of bytes pending in receive
buffer
WR: Ignored
RBUF_CNT [8..15] SIO receive buffer control
WR: Number of bytes to be read from the
receive FIFO
RD: Number of bytes left for readout
from the receive FIFO
- [16..31] Reserved
00Ch TRANSMIT_BUFFER_ST
ATUS_CONTRL
TBUF_ST [0..7] SIO output buffer status
RD: Space left in TX buffer
WR: Ignored
TBUF_CNT [8..15] SIO output buffer control
RD: Number of bytes written to transmit
FIFO
WR: Number of bytes to transmit
- [16..31] Reserved
010h
..
0FFh
- Reserved
100h SIO_DATA_REGISTER CHAR_0 [0..7] Character_0 RD: Read char. from receive
buffer WR: Write char. to transmit buffer
SIO_DATA_REGISTER CHAR_1 [8..15] Character_1 RD/WR
SIO_DATA_REGISTER CHAR_2 [16..23] Character_2 RD/WR
SIO_DATA_REGISTER CHAR_3 [24..31] Character_3 RD/WR
Offset Name Field Bit Description
Table 56: Serial input/output control and status register (SIO CSR)