FCC HDLC Controller
MPC8260 PowerQUICC II Family Reference Manual, Rev. 2
36-16 Freescale Semiconductor

Figure 36-8. HDLC Interrupt Event Example

36.10 FCC Status Register (FCCS)

The FCCS register, shown in Figure36-9, allows the user to monitor real-time status conditions on the

RXD line. The real-time status of the CTS and CD signals are part of the parallel I/O port; see Chapter 40,

“Parallel I/O Ports.”

01234567
Field FG — ID
Reset 0000_0000
R/W R
Addr 0x0x11318 (FCCS1), 0x0x11338 (FCCS2), 0x0x11358 (FCCS3)

Figure 36-9. FCC Status Register (FCCS)

CD IDL FLG RXB RXF IDL CD
Line Idle
Stored in Rx Buffer
RXD
CD
Frame
Received by HDLC
Time
Line Idle
TXD
RTS
Frame
Transmitted by HDLC
CTS
TXB CTCT
Line Idle Line Idle
Stored in Tx Buffer
Notes:
HDLC FCCE
Events
1. RXB event assumes rece ive buffers are 6 bytes ea ch.
2. The second IDL event occurs after 15 ones are received in a row.
3. The FLG interrup ts show the beginni ng and end of flag reception.
4. The FLG interrupt at the end of the frame may precede the RXF interrupt due to receive FIFO latency.
5. The CD event must be programmed in the parallel I/O port, not in the FCC itself.
Notes:
HDLC FCCE
Events
1. TXB event shown assume s all three bytes wer e put into a singl e buffer.
2. Example shows one additional opening flag. This is programmable.
FF AACI I ICRCRF
FLG FLG
FLG
6. F = flag, A = address byte, C = control byte, I = information byte, and CR = CRC byte
F F A A C CRCR F
3. The CT event must be programmed in the parallel I/O port, not in the FCC itself.