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XC161 Derivatives
Peripheral Units (Vol. 2 of 2)
Asynchronous/Synchronous Serial Interface (ASC)
User’s Manual
18-6
V2.2, 2004-01
ASC_X, V2.0
18.2.1
Asynchronous Data Frames
8-Bit Data Frames
8-bit data frames consist of either eight data bits D7 … D0 (M = 001
B
), or seven data bits
D6 … D0 plus an automatically generated parity bit (M = 011
B
). Parity may be odd or
even, depending on bit ODD. An even parity bit will be set if the modulo-2-sum of the
7 data bits is 1. An odd parity bit will be cleared in this case. Parity checking is enabled
via bit PEN (always OFF in 8-bit data mode). The parity error flag PE will be set, along
with the error interrupt request flag, if a wrong parity bit is received. The parity bit itself
will be stored in bit RBUF.7.
Figure 18-4
Asynchronous 8-Bit Frames
MCT05435
D0
LSB
Start
Bit
0
(2
nd
)
Stop
Bit
(1
st
)
Stop
Bit
D1
D2
D3
D4
D5
D6
D7
MSB
8 Data Bits
10-/11-bit UART Frame
1
1
M = 001
B
D0
LSB
Start
Bit
0
D1
D2
D3
D4
D5
D6
MSB
Parity
Bit
7 Data Bits
10-/11-bit UART Frame
1
1
M = 011
B
(2
nd
)
Stop
Bit
(1
st
)
Stop
Bit