HD64570 Datasheet, PDF (121/469 Pages) Hitachi Semiconductor – Serial Communications Adaptor

7
6
5
4
Async
PRTCL2PRTCL1PRTCL0AUTO
Byte sync
Bit sync HDLC
Read/Write R/W R/W R/W R/W
Initial value
0
0
0
0
3
2
1
0
—^*1 —^*1 STOP1 STOP0
CRCCCCRC1 CRC0
— R/W R/W R/W
0
0
0
0
Protocol mode
Auto-enable
000: Asynchronous mode 0: Auto-enable reset
001: Byte-sync
1: Auto-enable set
mono-sync mode
010: Byte-sync
Bi-sync mode
011: Byte-sync external
synchronous mode
100: Bit-sync HDLC mode
101: Reserved ^*2
110: Reserved ^*2
111: Reserved ^*2
CRC code calculation
• Byte/Bit synchronous
mode
0: Disable
1: Enable
Stop bit length
• Asynchronous mode
00: 1 bit
01: 1.5 bits
10: 2 bits
11: Reserved ^*2
CRC calculation
expression and
initial value ^*3
• Byte/Bit synchronous mode
0X: CRC-16
1X: CRC-CCITT
X0: Initial value = all 0s
X1: Initial value = all 1s
Notes: 1. Reserved. These bits always read 0 and must be set to 0.
2. Reserved. When these settings are selected, normal operation is not guaranteed.
3. X indicates any value (0 or 1).
Bits 7−5 (PRTCL2−PRTCL0: Protocol Mode): Specify the transmission protocol (transmission
control procedure). These bits must be initialized with a channel reset command before the bit
setting is changed. Otherwise, normal operation is not guaranteed.
PRTCL2, PRTCL1, PRTCL0 = 0, 0, 0: Specifies asynchronous mode
PRTCL2, PRTCL1, PRTCL0 = 0, 0, 1: Specifies byte synchronous mono-sync mode
PRTCL2, PRTCL1, PRTCL0 = 0, 1, 0: Specifies byte synchronous bi-sync mode
PRTCL2, PRTCL1, PRTCL0 = 0, 1, 1: Specifies byte synchronous external synchronous
mode
PRTCL2, PRTCL1, PRTCL0 = 1, 0, 0: Specifies bit synchronous HDLC mode
PRTCL2, PRTCL1, PRTCL0 = 1, 0, 1: Reserved
PRTCL2, PRTCL1, PRTCL0 = 1, 1, 0: Reserved
PRTCL2, PRTCL1, PRTCL0 = 1, 1, 1: Reserved
Bit 4 (AUTO: Auto-Enable): Controls the modem control signals (CTS, DCD, and RTS).
Rev. 0, 07/98, page 105 of 453