at85c51snd3b ATMEL Corporation, at85c51snd3b Datasheet - Page 215

• Manufacturer Part Number: at85c51snd3b
• Description: Single-chip Digital Audio Decoder - Encoder With Usb 2.0 Interface
• Manufacturer: ATMEL Corporation

Character Format
Start Field
Data Field
Parity Field
Stop Field
7632C–MP3–11/06
Figure 106. SIO Block Diagram
The character consists of five fields: start, data, parity, stop and guard fields.
Figure 107 shows a character example with 8 data bits, 1 parity bit, 2 stop bits and 2
guard bits.
Figure 107. Character Format Example
The start field is fixed and composed of 1 bit transmitted or received at low level.
The data field is composed of 7 or 8 bits by programming DLEN bit in SCON according
to Table 237. The least significant bit is always first transmitted.
Table 237. Data Bit Number Selection
The parity field is optional and enabled by PBEN bit in SCON. This field is composed of
1 bit and its mode is programmable by PMOD1:0 bits in SCON according to Table 238.
Table 238. Parity Mode Selection
The stop field is composed of 1 or 2 bits transmitted or received at high level by pro-
gramming STOP bit in SCON according to Table 239.
PMOD1
DLEN
0
1
0
0
1
1
Start
CLOCK
SIO
D0
CPU
DFC
Description
7-bit Data Length.
8-bit Data Length.
Bus
Bus
PMOD0
D1
SIO Interrupt
0
1
0
1
Request
Baud Rate
Generator
D2
Description
MARK: high Level
SPACE: Low Level
EVEN: High Level if the number of bits at high level in the data field is even.
ODD: Low Level if the number of bits at high level in the data field is odd.
D3
Data
D4
Char N
D5
Controller
Interrupt
D6
Transmitter
D7
Receiver
Parity
P
AT85C51SND3B
Stop 1
Stop 2
2 Guard Bits
Inter-Char
RXD
RTS
TXD
CTS
Char N+1
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