ATA6830 ATMEL Corporation, ATA6830 Datasheet - Page 7

• Manufacturer Part Number: ATA6830
• Description: Intelligent Stepper Motor Driver
• Manufacturer: ATMEL Corporation

4575C–BCD–05/03
Figure 6. Synchronization Sequence
Between two commands a pause has to be included. This is necessary for a clear rec-
ogition of a new message frame (command). Figure 7 shows the timing diagram of two
commands.
Figure 7. Message Frame and Space
Every command consists of 16 bits. They will be sent with two bytes. Figure 8 shows the
message frame. The high byte is sent first, immediately followed by the low byte. Every
byte starts with a start bit and ends with a parity bit and a stop bit. The first start bit (level
0) after a pause (level 1) indicates the beginning of a new message frame. The value of
the parity bit has to be odd, i.e., the crossfooting of the byte including the parity bit is
odd. If a data packet is not recognized due to a transmission error (parity error), the
entire command is rejected.
Figure 8. Command Bits
START
START
BIT
BIT
HIGH BYTE LOW BYTE
MESSAGE FRAME
7
6
5
8 DATA
HIGH BYTE
4
BITS
3
2
1
SYNCHRONIZATION PATTERN
0
PARITY
PARITY
MESSAGE FRAME
BIT
BIT
STOP
STOP
SPACE
BIT
BIT
START
START
BIT
BIT
7
6
5
8 DATA
LOW BYTE
4
BITS
3
2
1
ATA6830
0
PARITY
PARITY
BIT
BIT
STOP
STOP
BIT
BIT
7