MAX9268 Evaluation Kit

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The firmware also supports a small set of commands,

available when RTS is clear. Since all register read/

write requests are sent with RTS set, there is no conflict

between register data and firmware commands. These

firmware commands are issued automatically by the

MAX9249 EV kit software GUI. The following information

is provided for reference only.

Firmware command “?” prints the firmware version ban-

ner message and brief command list.

Firmware command “B” changes the baud rate by

changing the internal TH1 baud-rate divisor. Refer to

firmware help command “?” for details. Pressing switch

SW122 resets the USB baud rate to 921,600 baud. The

software GUI automatically sends the baud-rate change

command.

Firmware command “T” supports waking up the MAX9249

from the MAX9268 side of the link. Command “T” per-

forms a dummy read, followed by a delay on the order

of 1ms to 8ms, and finally writes a register value. For

example, send “T810558800483” to read from device

address 0x81 register 0x05, delay 4ms, then write to

device address 0x80 register 0x04 data 0x83. This is

the MAX9249 wake-up sequence for the default device

addresses. The software GUI automatically sends this

command when the Wake Up MAX9249 button is

pressed.

Table 1. MAX9268 EV Kit Jumper Descriptions

JUMPER

SIGNAL

SHUNT POSITION

DESCRIPTION

JU1

CDS

1-2

CDS = high; ECU attached to MAX9268; connects the USB to the

MAX9268 EV kit

2-3*

CDS = low; optional peripheral attached to the MAX9268

Open

Reserved

SW1

MS

1-2

(toggle switch up)

MS = high; full-duplex bypass mode; device registers not

accessible

2-3*

(toggle switch down)

MS = low; half-duplex base mode; required when writing to device

JU2

BWS

1-2*

BWS = high

2-3

BWS = low

JU3

EQS

1-2*

EQS = high

2-3

EQS = low

JU4

DRS

1-2*

DRS = high

2-3

DRS = low

JU5

SSEN

1-2*

SSEN = high

2-3

SSEN = low

JU6

PWDN

1-2*

PWDN = high

2-3

PWDN = low

JU7

ADD1

1-2

ADD1 = IOVDD (see Table 2)

1-3

ADD1 = Open (see Table 2)

1-4*

ADD1 = GND (see Table 2)

JU8

ADD0

1-2

ADD0 = IOVDD (see Table 2)

1-3

ADD0 = Open (see Table 2)

1-4*

ADD0 = GND (see Table 2)

JU9

Bus power

1-2*

J1 pin 4 connects to VIN

2-3

J1 pin 4 connects to GND

Open

J1 pin 4 unconnected

JU10

Bus power

1-2*

J1 pin 1 connects to USB+5V

Open

USB power is not connected to link cable power