Figure 636. Tx Fifo Pointers And Counter - STMicroelectronics SPC572L series Reference Manual

RM0400
Push FIFO
register
46.6.6.1 Address calculation for the first-in entry and last-in entry in the TX FIFO
The memory address of the first-in entry in the TX FIFO is computed by the following
equation:
Equation 25
First-in EntryAddress = TXFIFOBase + (4 × TXNXTPTR)
The memory address of the last-in entry in the TX FIFO is computed by the following
equation:
Equation 26
Last-in EntryAddress = TXFIFOBase + 4 × (TXCTR + TXNXTPTR –
1)mod(TXFIFOdepth)
TX FIFO Base – Base address of TX FIFO
TXCTR – TX FIFO Counter
TXNXTPTR – Transmit Next Pointer
TX FIFO Depth – Transmit FIFO depth, implementation specific
46.6.6.2 Address calculation for the first-in entry and last-in entry in the CMD FIFO
The memory address of the first-in entry in the CMD FIFO is computed by the following
equation:
Equation 27
First-in EntryAddress = CMDFIFOBase + (4 × CMDNXTPTR)
The memory address of the last-in entry in the CMD FIFO is computed by the following
equation:

Figure 636. TX FIFO pointers and counter

TX FIFO base
–
–
Entry A (first in)
Entry B
Entry C
Entry D (last in)
–
–
+ 1 TX FIFO counter
DocID027809 Rev 4
Deserial Serial Peripheral Interface (DSPI)
Transmit next
data pointer
(TXNXTPTR)
Shift register
– 1
SOUT
1219/2058
1220