
Communication Processor Module
MOTOROLA
MPC823 USER’S MANUAL
16-307
SCC2
COMMUNICATION
16
PROCESSOR
MODULE
UN—Underrun
This bit indicates that the serial communication controller has encountered a transmitter
underrun condition while transmitting the associated data buffer.
CT—CTS Lost
This bit indicates the CTS signal has been lost during frame transmission.
DATA LENGTH
This field represents the number of bytes that the communication processor module should
transmit from this buffer descriptor data buffer. It should be greater than zero and can be
even or odd. This value is never modified by the communication processor module.
TX DATA BUFFER POINTER
This field always points to the first byte of the associated data buffer. It can be even or odd,
and can reside in internal or external memory.
16.9.21.11 SCC2 TRANSPARENT EVENT REGISTER. When the SCC2 is in transparent
mode, the 16-bit, memory-mapped SCC2 event register is referred to as the SCC2
transparent event register (SCCE–Transparent). Since each protocol has specific
requirements, the SCCE bits are different for each implementation. This register is used to
report events recognized by the transparent channel and to generate interrupts. When an
event is recognized, the transparent controller sets the corresponding bit in this register.
Interrupts generated by this register can be masked in the SCCM–Transparent register.
A bit is reset by writing a 1 (writing a zero has no effect) and more than one bit can be reset
at a time. All unmasked bits must be reset before the communication processor module
negates the internal interrupt request signal. This register is cleared at reset and can be read
at any time.
Bits 0–2, 6–7, and 9–10—Reserved
These bits are reserved and should be set to 0.
GLR—Glitch on RX
This bit indicates that the the serial communication controller has found a glitch on the
receive clock.
SCCE–TRANSPARENT
BIT
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
FIELD
RESERVED
GLR
GLT
DCC
RES
GRA
RES
TXE
RCH
BSY
TX
RX
RESET
0
0000
00000
R/W
R/W
ADDR
(IMMR & 0xFFFF0000) + 0xA30