48SWTQFN-EP datasheet(83/103 Pages) MAXIM

83 / 103 page

MAX9288/MAX9290

3.12Gbps GMSL Deserializers

for Coax or STP Input and MIPI CSI-2 Output

www.maximintegrated.com

Maxim Integrated │ 83

Auto Error Reset

The default method to reset errors is to read the respec-

tive error registers in the deserializers (0x0D and 0x0E).

Auto error reset clears the error counters DECERR and

the ERR output ~1µs after ERR goes low. Auto error reset

is disabled on power-up. Enable auto error reset through

AUTORST (0x06, D5). Auto error reset does not run when

the device is in PRBS test mode.

Dual µC Control

Usually systems have one microcontroller to run the

control channel, located on the serializer side for display

applications or on the deserializer side for image-sensing

applications. However, a µC can reside on each side

simultaneously and trade off running the control channel.

In this case, each µC can communicate with the serializer

and deserializer and any peripheral devices.

Contention occurs if both µCs attempt to use the control

channel at the same time. It is up to the user to

prevent this contention by implementing a higher level

protocol. In addition, the control channel does not provide

arbitration between I2C masters on both sides of the

link. An acknowledge frame is not generated when

communication fails due to contention. If communication

across the serial link is not required, the µCs can disable

the forward and reverse control channel using the

FWDCCEN and REVCCEN bits (0x04, D[1:0]) in the

serializer/deserializer. Communication across the serial

link is stopped and contention between µCs cannot occur.

As an example of dual µC use in an image-sensing appli-

cation, the serializer can be in sleep mode and waiting

for wake-up by µC on the deserializer side. After wake-

up, the serializer-side µC assumes master control of the

serializer’s registers.

Changing the Clock Frequency

It is recommended that the serial link be enabled after the

video clock (fpixel) and the control-channel clock (fUART/

fI2C) are stable. When changing the clock frequency,

stop the video clock for 5µs, apply the clock at the new

frequency, then restart the serial link or toggle SEREN.

On-the-fly changes in clock frequency are possible if

the new frequency is immediately stable and without

glitches. The reverse control channel remains unavailable

for 500µs after serial link start or stop. When using the

UART interface, limit on-the-fly changes in fUART to

factors of less than 3.5 at a time to ensure that the device

recognizes the UART sync pattern. For example, when

lowering the UART frequency from 1Mbps to 100kbps,

first send data at 333kbps then at 100kbps for reduction

ratios of 3 and 3.333, respectively.

Spread-Spectrum Clock Tracking

Using a spread-spectrum clock source can reduce EMI/

EMC on the serial and MIPI data. The deserializer can

track a spread-spectrum signal from the serializer. Use

a spread < ±1% for CSI-2 output rates ≤ 400MHz. Use a

spread < ±0.5% for CSI-2 output rates > 400MHz.

Fast Detection of Loss-of-Synchronization

A measure of link quality is the recovery time from loss-

of-synchronization. The host can be quickly notified of

loss-of-lock by connecting the deserializer’s LOCK out-

put to the GPI input. If other sources use the GPI input,

such as a touch-screen controller, the µC can implement

a routine to distinguish between interrupts from loss-

of-sync and normal interrupts. Reverse control-channel

communication does not require an active forward link

to operate and accurately tracks the LOCK status of the

GMSL link. LOCK asserts for video link only and not for

the configuration link.

Providing a Frame Sync (Camera

Applications)

The GPI/GPO provide a simple solution for camera

applications that require a frame sync signal from the

ECU (e.g., surround-view systems). Connect the ECU

frame sync signal to the GPI input, and connect GPO

output to the camera frame sync input. GPI/GPO has

a typical delay of 275µs. Skew between multiple GPI/

GPO channels is typically 115µs. If a lower skew signal is

required, connect the camera’s frame sync input to one of

the deserializer’s GPIOs and use an I2C broadcast write

command to change the GPIO output state. This has a

maximum skew of 1.5µs, independent from the used I2C

bit rate.

Software Programming of the Device

Addresses

The serializers and deserializers have programmable

device addresses. This allows multiple GMSL devices,

along with I2C peripherals, to coexist on the same control

channel. The serializer device address is in register 0x00

of each device, while the deserializer device address is in

first write to the device whose address changes (register

0x00 of the serializer for serializer device address change,

or register 0x01 of the deserializer for deserializer device

address change). Then write the same address into the

corresponding register on the other device (register 0x00

of the deserializer for serializer device address change,

or register 0x01 of the serializer for deserializer device

address change).

48SWTQFN-EP Datasheet(PDF) 83 Page - Maxim Integrated Products

48SWTQFN-EP Datasheet(HTML) 83 Page - Maxim Integrated Products

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

Datasheet Download

Link URL