z85230 ZiLOG Semiconductor, z85230 Datasheet - Page 58

• Manufacturer Part Number: z85230
• Description: Enhanced Serial Communications Controller
• Manufacturer: ZiLOG Semiconductor

Table 24. Write Register 15
PS005303-0907
Bit
R/W
Reset
R = Read W = Write X = Indeterminate
Bit
Position
7
6
5
4
3
2
1
0
Read Registers
The ESCC contains ten read registers (eleven, counting the receive buffer RR8) in each
channel. Four of these may be read to obtain status information (RR0, RR1, RR10 and
RR15).
Two registers, RR12 and RR13, are read to learn the BRG time constant. RR2 contains
either the unmodified interrupt vector, Channel A, or the vector modified by status infor-
mation, Channel B.
RR3 contains the Interrupt Pending (IP) bits for Channel A.
RR6 and RR7 contain the information in the SDLC Frame Status FIFO, but is only read
when WR15 bit 2 is 1. If WR7’ bit 6 is 1, Write Registers WR3, WR4, WR5, and WR10
can be read as RR9, RR4, RR5, and RR14, respectively.
describe the format of the read registers.
R/W
7
1
Value
6
1
Description
Break/Abort Interrupt Enable
Tx Underrun/EOM Interrupt Enable
CTS Interrupt Enable
Sync/Hunt
DCD Interrupt Enable
SDLC FIFO Enable
Zero Count Interrupt Enable
WR7’ SDLC Feature Enable
5
1
4
1
W
3
0
Table 25
2
0
Product Specification
through
Z85230/Z80230
1
0
Table 40
Programming
0
0
53