Memory Map/Register Definition
MCF548x Reference Manual, Rev. 3
Freescale Semiconductor 19-39

Table 19-36. PCIRER Field Descriptions

Bits Name Description
31 RC Reset controller. User writes this bit high to put Receive Controller in a reset state. Note that other
register bits are not affected. This Reset is intended for recovery from an error condition or to reload
the Start Address when Continuous mode is selected. This Reset bit does not prohibit register
access but it must be negated in order to initiate a Restart sequence (ie writing the Packet_Size
register). If it is used to reload a Start Address then the Start_Add register must be written prior to
deasserting this Reset bit.
30 RF Reset FIFO. The FIFO will be reset and flushed of any existing data when set high. The Reset
Controller bit and the Reset FIFO bit operate independently, but clearly both must be low for normal
operation.
29 FE Flush enable. This is an important bit which causes a flush signal to be generated to the Receive
FIFO Controller when the end of the current packet occurs. This Flush is necessary to insure that
the Multi-Channel DMA will get all data left in the Receive FIFO. FE is active high.
28 CM Continuous mode. User writes this bit high to activate Continuous mode. In Continuous mode the
Start_Add value is ignored at each packet restart and the PCI address is auto-incremented from one
packet to the next. Also, the Packets_Done status byte will become active, indicating how many
packets have been received since the last Reset Controller condition. If the Continuous bit is low,
software is responsible for updating the Start_Add value at each packet Restart.
27 BE Bus error enable. User writes this bit high to enable Bus Error indications. Setting this bit allows the
errors indicated by BE1, BE2, and BE3 in PCIRSR to generate a bus error, which can result in a
TEA on the XL bus.. See Section 19.3.3.2.7, “Rx Status Register (PCIRSR),” for Bus Error
descriptions. Normally this bit will be 0 since illegal Slave bus accesses are not destructive to
register contents, although it may indicate broken software. Note that this bit does not affect
interrupt generation.
26–25 Reserved, should be cleared.
24 ME Master enable. This is the Receive Controller master enable signal. User must write it high to
enable operation. It can be toggled low to permit out-of-order register updates prior to generating a
Restart sequence (in which case transmission will begin when Master Enable is written back high),
but it should not be used as such in Continuous mode because it can have the side effect of reset-
ting the Packets_Done status counter.
23–22 Reserved, should be cleared.
21 FEE FIFO error enable. User writes this bit high to enable CPU Interrupt generation in the case of FIFO
error termination of a packet transmission. It may be desirable to mask CPU interrupts in the case
that Multi-Channel DMA is controlling operation, but in such a case software should poll the status
bits to prevent a possible lock-up condition.
20 SE System error enable. User writes this bit high to enable CPU Interrupt generation in the case of
system error termination of a packet transmission. It may be desirable to mask CPU interrupts in
the case that Multi-Channel DMA is controlling operation, but in such a case someone should be
polling the status bits to prevent a possible lock-up condition.
19 RE Retry abort enable. User writes this bit high to enable CPU Interrupt generation in the case of retry
abort termination of a packet transmission. It may be desirable to mask CPU interrupts in the case
that Multi-Channel DMA is controlling operation, but in such a case, software should poll the status
bits to prevent a possible lock-up condition.
18 TAE Target abort enable. User writes this bit high to enable CPU Interrupt generation in the case of tar-
get abort termination of a packet transmission. It may be desirable to mask CPU interrupts in the
case that Multi-Channel DMA is controlling operation, but in such a case software should poll the
status bits to prevent a possible lock-up condition.