mcf51ac256a Freescale Semiconductor, Inc, mcf51ac256a Datasheet - Page 460

• Manufacturer Part Number: mcf51ac256a
• Description: Mcf51ac Flexis
• Manufacturer: Freescale Semiconductor, Inc

16-Bit Serial Peripheral Interface (SPI16)
20.4.4
SPI works in FIFO mode when SPIxC3[0] bit is set. When in FIFO mode SPI RX buffer and SPI TX buffer
is replaced by a 8 byte deep fifo as shown in figure above.
20-20
SPI FIFO MODE
MCF51AC256 ColdFire Integrated Microcontroller Reference Manual, Rev. 5
Figure 20-14. SPIDH:L read side structural overview in FIFO mode
SPI_CORE_SHFR
SPI_REG_BLOCK
Figure 20-15. SPIDH:L write side structural overview in FIFO mode
Read
Control
SPI Data Register
FIFO Ctrlr
Read Access
FIFO Ctrlr
Control
Load
Write Access
spidh:l_rx_reg
shfr_rx_reg
spidh:l_tx_reg
shfr_tx_reg
RX- FIFO
IPBus (ips_rdata[7:0])
FIFO depth = 8 bytes
IPBus (ips_wdata)
TX FIFO
FIFO depth = 8 bytes
SPI_CORE_SHFR
SPI Data Register
SPI_REG_BLOCK
Freescale Semiconductor