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146
•
‘Receiver overrun’ (generated when received data is dropped due to a reception overrun)
•
‘CLTU ready’ (note that this interrupt is also issued for abandoned CLTUs)
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FAR interrupt ‘Status Survey Data’
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CLCW interrupt ‘Bit Lock’
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CLCW interrupt ‘RF Available’
13.7.1 Miscellaneous
The accuracy of the transmission or reception baud rate of the bit asynchronous serial interface is
dependent on the selected system frequency and baud rate. The number of system clock periods used
for sending or receiving a bit is directly proportional to the integer part of the division of the system
frequency with the baud rate.
The BREAK command received on the bit asynchronous serial interface is a sequence of logical zeros
that is at least one bit period longer than the normal byte frame, i.e. start bit, eight data bits, optional
parity, one or two stop bits. When transmitted, it is always 13 bits.
13.8
Interrupts
The core generates the interrupts defined in table 173.
Table 173.Interrupts
13.9
Interrupt offset
Interrupt name
Description
1:st
RFA
RF Available changed
2:nd
BLO
Bit Lock changed
3:rd
FAR
FAR available
4:th
CR
CLTU ready/aborted
5:th
RBF
Output buffer full
6:th
OV
Input data overrun
7:th
CS
CLTU stored
Miscellaneous
13.9.1 Numbering and naming conventions
Convention according to the CCSDS recommendations, applying to time structures:
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The most significant bit of an array is located to the left, carrying index number zero.
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An octet comprises eight bits.
Table 174.CCSDS n-bit field definition
CCSDS n-bit field
most significant
0
least significant
1 to n-2
n-1
Convention according to AMBA specification, applying to the APB/AHB interfaces:
•
Signal names are in upper case, except for the following:
•
A lower case 'n' in the name indicates that the signal is active low.
•
Constant names are in upper case.
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The least significant bit of an array is located to the right, carrying index number zero.