Commodore Amiga A1000, Hardware Reference Manual

Page: 261 / 380

Table 8-9 shows the definitions of the various bit positions within SERDATR.
Table 8-9: SERDATR / ADKCON Registers
SERDATR
Bit
Number Name Function
15 OVRUN OVERRUN bit
(Mirror - also appears in the interrupt request
register.) Indicates that another byte of data was
received before the previous byte was picked up by the
processor. To prevent this condition, it is necessary
to reset INTF_RBF (bit 11, receive-buffer-full) in
INTREQ.
14 RBF READ BUFFER FULL
(Mirror - also appears in the interrupt request
register.) When this bit is 1, there is data ready to
be picked up by the processor. After reading the
contents of this data register, you must reset the
INTF_RBF bit in INTREQ to prevent an overrun.
13 TBE TRANSMIT BUFFER EMPTY
(Not a mirror-interrupt occurs when the buffer becomes
empty.) When bit 14 is a 1, the data in the output data
register (SERDAT) has been transferred to the serial
output shift register, so SERDAT is ready to accept
another output word. This is also true when the buffer
is empty.
This bit is normally used for full-duplex operation.
12 TSRE TRANSMIT SHIFT REGISTER EMPTY
When this bit is a 1, the output shift register has
completed its task, all data has been transmitted, and
the register is now idle. If you stop writing data into
the output register (SERDAT), then this bit will become
a 1 after both the word currently in the shift register
and the word placed into SERDAT have been transmitted.
This bit is normally used for half-duplex operation.
11 RXD Direct read of RXD pin on Paula chip.
10 Not used at this time.
9 STP Stop bit if 9 data bits are specified for receive.
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