HD64570 Datasheet, PDF (129/469 Pages) Hitachi Semiconductor – Serial Communications Adaptor

Bits 7−6 (BRATE1−BRATE0/ADDRS1−ADDRS0: Bit Rate/Address Field Check): Specify
the relationship between the bit rate and the transmit/receive clock in asynchronous mode, and the
checking method for the address field in bit synchronous mode. These bits are used for both
transmission and reception.
• Asynchronous mode
BRATE1, BRATE0 = 0, 0: Bit rate = 1/1 clock rate
BRATE1, BRATE0 = 0, 1: Bit rate = 1/16 clock rate
BRATE1, BRATE0 = 1, 0: Bit rate = 1/32 clock rate
BRATE1, BRATE0 = 1, 1: Bit rate = 1/64 clock rate
For details on asynchronous mode, see section 5.3.1, Asynchronous Mode.
• Byte synchronous mode
Reserved. These bits always read 0 and must be set to 0.
• Bit synchronous mode
ADDRS1, ADDRS0 = 0, 0: Disables the address field check
ADDRS1, ADDRS0 = 0, 1: Sets single address 1
ADDRS1, ADDRS0 = 1, 0: Sets single address 2
ADDRS1, ADDRS0 = 1, 1: Sets dual address
For details, see Address Field Check, in section 5.3.4, Bit Synchronous Loop Mode.
Bits 5−4 (TXCHR1−TXCHR0: Transmit Character Length): Specify the character length of
the transmit data in asynchronous mode. Rewriting these bits during operation updates the
character length for subsequent transmit characters.
• Asynchronous mode
TXCHR1, TXCHR0 = 0, 0: 8 bits/character
TXCHR1, TXCHR0 = 0, 1: 7 bits/character
TXCHR1, TXCHR0 = 1, 0: 6 bits/character
TXCHR1, TXCHR0 = 1, 1: 5 bits/character
• Byte synchronous/Bit synchronous mode
Reserved. These bits always read 0 and must be set to 0.
Bits 3−2 (RXCHR1−RXCHR0: Receive Character Length): Specify the character length of
the receive data in asynchronous mode. Rewriting these bits during operation updates the
character length for subsequent receive characters.
• Asynchronous mode
RXCHR1, RXCHR0 = 0, 0: 8 bits/character
RXCHR1, RXCHR0 = 0, 1: 7 bits/character
RXCHR1, RXCHR0 = 1, 0: 6 bits/character
Rev. 0, 07/98, page 113 of 453