Scc Ethernet Event Register (Scce)/Mask Register (Sccm) - Freescale Semiconductor MPC850 User Manual

SCC Ethernet Event Register (SCCE)/Mask Register (SCCM)

Table 27-8. SCC Ethernet TxBD Status and Control Field Descriptions (Continued)
Bits Name
14 UN Underrun. Set when the Ethernet controller encounters a transmitter underrun while sending the
buffer. The Ethernet controller writes UN after it finishes sending the buffer.
15 CSL Carrier sense lost. Set when carrier sense is lost during frame transmission. The Ethernet controller
writes CSL after it finishes sending the buffer.
Data length and buffer pointer fields are described in Section 21.3, "SCC Buffer
Descriptors (BDs)."
27.20 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 27-9. SCC Ethernet Event Register (SCCE)/Mask Register (SCCM)
Figure 27-9 describes SCCE and SCCM fields.
Bits Name
0–7 — Reserved, should be cleared.
8 GRA Graceful stop complete. Set as soon the transmitter finishes any frame that was in progress when a
GRACEFUL STOP TRANSMIT
9–10 — 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.
13 BSY Busy condition. Set when a frame is received and discarded due to a lack of buffers.
14 TXB Tx buffer. Set when a buffer has been sent on the Ethernet channel.
15 RXB Rx buffer. Set when a buffer that was not a complete frame was received on the Ethernet channel.
3 4 5 6
—
0000_0000_0000_0000
0xA30 (SCCE2)/0xA34 (SCCM2); 0xA50 (SCCE3)/0xA54 (SCCM3)
Table 27-9. SCCE/SCCM Field Descriptions
command was issued. It is set immediately if no frame was in progress.
MPC850 Family User's Manual
Description
7 8 9 10
GRA — TXE RXF BSY TXB RXB
R/W
Description
11 12 13 14 15