CD2481 Datasheet, PDF (139/222 Pages) Intel Corporation – Programmable Four-Channel Communications Controller

Programmable Four-Channel Communications Controller — CD2481
9.2.10.2 Special Character Range high (SCRh)
Register Name: SCRH
Register Description: Special Character Range, high
Default Value: x’00
Access: Byte Read/Write
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
User Defined Special Character Detect Range, high
Intel Hex Address: x’21
Motorola Hex Address: x’22
Bit 1
Bit 0
9.2.11
These registers define an inclusive range for special character recognition in the Asynchronous
mode. It can be useful for identifying that a received character is within a user defined range and is,
for example, a control character.
LNext Character (LNXT) – Async Mode Only
Register Name: LNXT
Register Description: Literal Next Character
Default Value: x’00
Access: Byte Read/Write
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
User Defined Literal Next Character
Intel Hex Address: x’2D
Motorola Hex Address: x’2E
Bit 1
Bit 0
9.2.12
9.2.12.1
This register defines the LNext character. If the LNext function is enabled (bit 6 of COR7), the
CD2481 examines received characters and compare them against this value. If a match occurs, this
character and the following are placed in the FIFO without any special processing. In effect, the
LNext function causes the CD2481 to ignore characters with special meaning, such as flow control
characters. There are two exceptions: a ‘break’ or an ‘errored’ character. If the character following
the LNext character is either a ‘break’ or an ‘errored’ character, LNext is placed in the FIFO, and
the following character is treated as it normally would be for these error conditions.
Receive Frame Address Registers – HDLC Sync Mode Only
Receive Frame Address Register 1 (RFAR1)
Register Name: RFAR1
Register Description: Receive Frame Address Register 1
Default Value: x’00
Access: Byte Read/Write
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Frame Qualification Address 1
Bit 2
Intel Hex Address: x’1C
Motorola Hex Address: x’1F
Bit 1
Bit 0
Datasheet
139