MCF548x Reference Manual, Rev. 3
19-24 Freescale Semiconductor

19.3.3.1.2 Tx Start Address Register (PCITSAR)

Table 19-19. PCITPSR Field Descriptions

Bits Name Description
31–18 Packet_Size Packet_Size [15:2]. The Packet_Size field indicates the number of bytes for the transmit controller
to send over PCI. Only bits [15:2] are writable. Only 32-bit data transfers to the FIFO are allowed.
Writing to this register also completes a Restart Sequence as long as the Master Enable bit,
PCITER[ME], is high and Reset Controller bit, PCITER[RC], is low.
17–16 Packet_Size [1:0] The two low bits are hardwired low.
15–0 Reserved, should be cleared.
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
RStart_Add
W
Reset0000000000000000
1514131211109876543210
RStart_Add
W
Reset0000000000000000
Reg
Addr
MBAR + 0x8404

Figure 19-21. Tx Start Address Register (PCITSAR)

Table 19-20. PCITSAR Field Descriptions

Bits Name Description

31–0 Start_Add User writes the PCI address to be presented for the first DWORD of a PCI packet. The PCI Tx
controller will track and calculate the necessary address for subsequent transactions. Addressing
is assumed to be sequential from the start address unless the PCITTCR[DI] bit is set. This register
will not increment as the PCI packet proceeds.