Controlling and Resetting the Port
9-9
Synchronous Serial Port
Table 9–2. Run and Emulation Modes
ÁÁÁ
ÁÁÁ
FREE
ÁÁÁÁ
ÁÁÁÁ
SOFT
ÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁ
Run/Emulation Mode
ÁÁÁ
ÁÁÁ
0
ÁÁÁÁ
ÁÁÁÁ
0
ÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁ
Immediate stop
ÁÁÁ
Á
Á
Á
ÁÁÁ
0
ÁÁÁÁ
Á
ÁÁ
Á
ÁÁÁÁ
1
ÁÁÁÁÁÁÁ
Á
ÁÁÁÁÁ
Á
ÁÁÁÁÁÁÁ
Stop after completion
of word
ÁÁÁ
ÁÁÁ
1
ÁÁÁÁ
ÁÁÁÁ
0
ÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁ
Free run
ÁÁÁ
Á
Á
Á
ÁÁÁ
1
ÁÁÁÁ
Á
ÁÁ
Á
ÁÁÁÁ
1
ÁÁÁÁÁÁÁ
Á
ÁÁÁÁÁ
Á
ÁÁÁÁÁÁÁ
Free run
Note:
If an option besides immediate stop is chosen for the receiver, an overflow
error is possible. The default mode (selected at reset) is
immediate stop.
Bit 13
TCOMP — Transmission complete. This bit is cleared to 0 when all data
in the transmit FIFO buffer has been transmitted (the buffer is empty) and is
set to 1 when new data is written to the transmit FIFO buffer (the buffer is not
empty).
Bit 12
RFNE — Receive FIFO buffer not empty bit. This bit is 1 when the receive
FIFO buffer contains data and is cleared when the buffer empties.
Bits 11–10
FT1, FT0 — FIFO transmit-interrupt bits. The values you write to FT0 and
FT1 set an interrupt trigger condition based on the contents of the transmit
FIFO buffer. When this condition is met, a transmit interrupt (XINT) is gener-
ated and the data can be transferred out to the FIFO buffer using the OUT
instruction. Table 9–3 summarizes the possible trigger conditions.
Table 9–3. Controlling Transmit Interrupt Generation by Writing to Bits FT1 and FT0
ÁÁÁÁÁ
ÁÁÁÁÁ
Select Bits
ÁÁ
ÁÁ
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ
ÁÁÁ
ÁÁÁ
FT1
ÁÁÁ
ÁÁÁ
FT0
ÁÁ
ÁÁ
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ
Generate XINT when...
ÁÁÁ
Á
Á
Á
ÁÁÁ
0
ÁÁÁ
Á
Á
Á
ÁÁÁ
0
ÁÁ
ÁÁ
ÁÁ
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ
Á
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ
Á
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ
Transmit FIFO buffer can accept one or more words;
XINT occurs repeatedly until the buffer is full.
ÁÁÁ
Á
Á
Á
ÁÁÁ
0
ÁÁÁ
Á
Á
Á
ÁÁÁ
1
ÁÁ
ÁÁ
ÁÁ
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ
Á
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ
Á
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ
Transmit FIFO buffer can accept two or more words;
XINT occurs repeatedly until three words are written.
ÁÁÁ
Á
Á
Á
ÁÁÁ
1
ÁÁÁ
Á
Á
Á
ÁÁÁ
0
ÁÁ
ÁÁ
ÁÁ
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ
Á
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ
Á
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ
Transmit FIFO buffer can accept three or four words;
XINT occurs repeatedly until two words are written.
ÁÁÁ
Á
Á
Á
ÁÁÁ
1
ÁÁÁ
Á
Á
Á
ÁÁÁ
1
ÁÁ
ÁÁ
ÁÁ
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ
Á
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ
Á
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ
Transmit FIFO buffer is empty (can accept 4 words);
XINT occurs repeatedly until one word is written.