Motorola MPC860 PowerQUICC User Manual page 788

Part V. The Communications Processor Module
29.12 SCC Transparent Event Register (SCCE)/Mask
Register (SCCM)
When the SCC is in transparent mode, the SCC event register (SCCE) functions as the
transparent event register to report events recognized by the transparent channel and to
generate interrupts. When an event is recognized, the transparent controller sets the
corresponding SCCE bit. Interrupts are enabled by setting, and masked by clearing, the
equivalent bits in the transparent mask register (SCCM).
Event bits are reset by writing ones; writing zeros has no effect. All unmasked bits must be
reset before the CPM negates the internal interrupt request signal. Figure 29-4 shows the
event and mask registers.
Bit 0 1
Field Ñ
Reset
R/W
Address
Figure 29-4. SCC Transparent Event Register (SCCE)/Mask Register (SCCM)
Table 29-9 describes SCCE/SCCM Þelds.
Bit Name
0Ð2 Ñ Reserved, should be cleared.
3 GLR Glitch on Rx. Set when the SCC Þnds a glitch on the receive clock.
4 GLT Glitch on Tx. Set when the SCC Þnds a glitch on the transmit clock.
5 DCC DPLL CS changed. Set when the DPLL-generated carrier sense status changes (valid only when the
DPLL is used). Real-time status can be read in SCCS. This is not the CD status mentioned elsewhere.
6Ð7 Ñ Reserved, should be cleared.
8 GRA Graceful stop complete. Set when a graceful stop initiated by completes as soon as the transmitter
Þnishes any frame in progress when the
if no frame was in progress when the command was issued.
9Ð10 Ñ Reserved, should be cleared.
11 TXE Tx error. Set when an error occurs on the transmitter channel.
12 Ñ Reserved, should be cleared.
13 BSY Busy condition. Set when a byte or word is received and discarded due to a lack of buffers. The
receiver resumes reception after it gets an
29-12
2 3 4 5 6
GLR GLT DCC
0000_0000_0000_0000
0xA10 (SCCE1)/0xA34 (SCCM1); 0xA30 (SCCE2)/0xA34 (SCCM2)
0xA50 (SCCE3)/0xA54 (SCCM3); 0xA70 (SCCE4)/0xA74 (SCCM4)
Table 29-9. SCCE/SCCM Field Descriptions
MPC860 PowerQUICC UserÕs Manual
7 8 9 10
Ñ GRA Ñ
R/W
Description
command was issued. Immediately
GRACEFUL STOP TRANSMIT
command.
ENTER HUNT MODE
11 12 13 14
TXE Ñ BSY TXB RXB
MOTOROLA
15