MAX9257GTL/V+T Maxim Integrated Products, MAX9257GTL/V+T Datasheet - Page 35

• Manufacturer Part Number: MAX9257GTL/V+T
• Description: IC SER/DESER PROG 40TQFN-EP
• Manufacturer: Maxim Integrated Products

Specifications of MAX9257GTL/V+T

• Function: Serializer/Deserializer
• Data Rate: 840Mbps
• Input Type: Serial
• Output Type: LVDS
• Number Of Inputs: 16
• Number Of Outputs: 1
• Voltage - Supply: 3 V ~ 3.6 V
• Operating Temperature: -40°C ~ 105°C
• Mounting Type: Surface Mount
• Package / Case: 40-TQFN Exposed Pad
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

sent, but since CTO timed out, bypass mode ends and
base mode is active for the next vertical blanking period.
With STO > CTO > ETO, bypass mode can be made
continuous by having the ECU send real commands or
dummy commands (such as a command to a nonexist-
ing address) each time the control channel opens.
Then the ECU does not have to send a command to
enter bypass mode each time it wants to program the
peripheral device.
The UART frame used to program the MAX9257 and
the MAX9258 has a low start bit, eight data bits, an
even parity bit and a high stop bit. The data following
the start bit is the LSB. With even parity, when there are
an odd number of 1s in the data bits (D0 through D7)
the parity bit is set to 1. The stop bit is sampled and if it
is not high, a frame error is generated (Figure 26).
Figure 25. UART-to-I
Figure 26. UART Frame Format
Figure 27. UART Synchronization Frame
START
0
START
0
Fully Programmable Serializer/Deserializer
S
0
I
2
C SLAVE ADDRESS + Wr
SLAVE ADDRESS
4
2
C Conversion
______________________________________________________________________________________
1
SYNCHRONIZATION FRAME
D0
0
1
W
D1
0
A
5
UART Frame Format
LSB
1
MSB
D2
0
REG ADDRESS
REG ADDR
with UART/I
1
MAX9257
ECU
PARITY
1
D3
UART
LSB
MSB LSB
UART
STOP
A
I
2
C
MAX9258
D4
MSB
PERIPHERAL
The synchronization frame must precede any read or
write packets (Figure 26). Transitions in the frame cali-
brate the oscillators on the MAX9257/MAX9258. The
baud rate of the synchronization frame sets the operat-
ing baud rate of the control channel. At power-up,
UART data rate must be between 95kbps to 400kbps.
After power-up, UART data rate can be programmed
according to Tables 28 and 29. Data is serialized start-
ing with the LSB first. The synchronization frame is 0x54
as shown in Figure 27.
The ECU writes the sync frame, 7-bit device address
plus read/write bit (R/W = 0 for write), 8-bit register
address, number of bytes to be written, and data bytes
(Figure 28). The ECU must follow this UART protocol to
correctly program the MAX9257/MAX9258.
Figure 28. UART Write Packet to MAX9257/MAX9258
DATA 0
DATA 0
SYNC
D5
2
DEV ADDR +
LSB
MSB
C Control Channel
R/W
A
D6
REG ADDRESS
LSB
D7
UART Synchronization Frame
MSB
NUMBER OF BYTES
DATA N
DATA N
PARITY
MSB
LSB
STOP
BYTE 1
A
Write Packet
P
BYTE N
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