Zilog Z16C35 - Manual (Page 65)

ISCC
User Manual
UM011002-0808
59
At this point, the other registers should be initialized as necessary. When all of this is com-
pleted the transmitter maybe enabled by setting bit 3 of WR5 to one. Now that the trans-
mitter is enabled the CRC generator maybe initialized by issuing the Reset Tx CRC
Generator command in WR0, bit 6-7.
4.3.2 Byte-Oriented Synchronous Receive
The CPU places the receiver in Hunt mode whenever transmission begins (or whenever a
data dropout has occurred and the hardware determines that resynchronization is neces-
sary). In Hunt mode, the receiver shifts a bit into the Receive Shift register and compares
the contents of the Receive Shift register and with the sync character (stored in another
register), repeating the process until a match occurs. When a match occurs, the receiver
begins transferring bytes to the receive FIFO.
Once the sync character-oriented mode has been selected, any of the four sync character
length maybe selected: 6-bits, 8-bits, 12-bits, or 16-bits.
The Table 4-7 shows the WR register bit setting for selecting sync character length.
Table 4-7. Sync Character Length Selection
The arrangement of the sync character in WR6 and WR7 is shown in Figure 4-5.
5,6 select number of bits
per character
WR10 7 CRC preset value
Table 4–15. Sync Character Length Selection
Sync Length WR4,D5 WR4,D4 WR10,D0
6 bits 0 0 1
8 bits 0 0 0
12 bits 0 1 1
16 bits 0 1 0
Table 4–14. Transmitter Initialization in Character Oriented Mode
Register Bit No Description
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