Table of Contents
Advertisement
Table 28-8. SCC Ethernet Receive TxBD Status and Control Field Descriptions
Bits
Name
10Ð13
RC
Retry count. Indicates the number of retries required before the frame was sent successfully. If RC =
0, the frame was sent correctly the Þrst time. If RC = 15 and RET_LIM = 15 in the parameter RAM, 15
retries were required. Because the counter saturates at 15, if RC = 15 and RET_LIM > 15, then 15 or
more retries were required. The controller writes this Þeld after it successfully sends the buffer.
14
UN
Underrun. Set when the Ethernet controller encounters a transmitter underrun while sending the
buffer. The Ethernet controller writes UN after it Þnishes sending the buffer.
15
CSL
Carrier sense lost. Set when carrier sense is lost during frame transmission. The Ethernet controller
writes CSL after it Þnishes sending the buffer.
Data length and buffer pointer Þelds are described in Section 22.2, ÒSCC Buffer
Descriptors (BDs).Ó
28.21 SCC Ethernet Event Register (SCCE)/Mask
Register (SCCM)
The SCC event register (SCCE) is used as the Ethernet event register to generate interrupts
and report events recognized by the Ethernet channel. When an event is recognized, the
Ethernet controller sets the corresponding SCCE bit. Interrupts are enabled by setting, and
masked by clearing, the equivalent bits in the Ethernet mask register (SCCM). SCCE bits
are cleared by writing ones; writing zeros has no effect. All unmasked bits must be cleared
before the CPM clears the internal interrupt request.
Bit
0
1
2
Field
Reset
R/W
Addr
Figure 28-11. SCC Ethernet Event Register (SCCE)/Mask Register (SCCM)
Table 28-9 describes SCCE and SCCM Þelds.
Bits Name
0Ð7
Ñ
Reserved, should be cleared.
8
GRA
Graceful stop complete. Set as soon the transmitter Þnishes any frame that was in progress when a
GRACEFUL STOP TRANSMIT
9Ð10 Ñ
Reserved, should be cleared.
11
TXE
Set when an error occurs on the transmitter channel.
12
RXF
Rx frame. Set when a complete frame has been received on the Ethernet channel.
MOTOROLA
3
4
5
6
Ñ
0000_0000_0000_0000
0xA10 (SCCE1)/0xA34 (SCCM1); 0xA30 (SCCE2)/0xA34 (SCCM2)
0xA50 (SCCE3)/0xA54 (SCCM3); 0xA70 (SCCE4)/0xA74 (SCCM4)
Table 28-9. SCCE/SCCM Field Descriptions
command was issued. It is set immediately if no frame was in progress.
Chapter 28. SCC Ethernet Mode
Part V. The Communications Processor Module
Description
7
8
9
10
11
GRA
Ñ
TXE RXF BSY TXB RXB
R/W
Description
12
13
14
15
28-25
Advertisement
Table of Contents
