NEC V850E/RS1, Руководство пользователя, Страница: 473 / 852

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Chapter 14 Queued CSI (CSI30, CSI31)
User’s Manual U16702EE3V2UD00
Figure 14-8: FIFO Buffer Status Registers (SFA0, SFA1) Format (2/2)
Remark: Read only
Remark: Read only
Remarks: 1. Read only bit.
2. This bit is cleared to “0” by POWER = 0 or (CTXE = 0 and CRXE = 0).
3. In Single Buffer Transfer Mode, this bit holds “1” from transmission start to FIFO empty.
4. In FIFO Buffer Transfer Mode, this bit holds “1” from transmission start until finish trans-
ferring all data to be sent.
Remarks: 1. Read only bits.
2. SFP3 -
SFP
0 holds its value until RESET or FPCLR = 1.
Caution: SFFUL, SFEMP, CSOT and SFP3 - SFP0 are continuously updated with the current
status of the Queued CSI. This means that a value read might be outdated shortly
after the read was executed.
When writing accidentally a 17th data element in FIFO, an overflow interrupt
(INTC3nO) will occur to indicate the error.
SFFUL FIFO buffer full status flag
0 FIFO buffer is not full
1 FIFO buffer is full
SFEMP FIFO buffer empty status flag
0 FIFO buffer is not empty
1 FIFO buffer is empty
CSOT Transmission status flag
0 Idle state
1 Transmission in on going or preparing
SFP3 - SFP0 Transmission data count
nnnnH
In Single transfer mode, SFP3 - SFP0 indicates the number of remaining transfers in the
FIFO. This value can be understood as:
(Write FIFO pointer) - (SIO load pointer)
SFP3 - SFP0 is read only in Single transfer mode.
In FIFO transfer mode,SPF3 - SFP0 indicates the number of data transfers completed.
In case of SFP3 - SFP0 = 0H:
- SFEMP = 0, SFP3 - SFP0 = 0H: Number of receptions completed = 0
- SFEMP = 1, SFP3 - SFP0 = 0H: Number of receptions completed = 16
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