Other Parts Discussed in Thread: TSER953,
Hello,
We have a MIPI camera system with the TDES960 and the TSER953. We cannot achieve a back channel frequency of 50MHz.
Our REFCLK for the TDES960 is 25MHz.
The MODE pin on the TDES960 is strapped for CSI-2 Synchronous mode. (Vmode = 0.995V).
We have verified the MODE strapping by reading BCC_CONFIG[0x58] = 0x1E (back channel enable = 1, back channel CRC enable = 1, back channel frequency select = 50Mbps)
In this configuration, we cannot establish a link between the TDES960 and the TSER953.
If we change the back channel frequency select to 10 Mbps (BCC_CONFIG=0x1A), we can establish a link.
The serializer register MODEL_SEL[0x03] = 0x48 indicating CSI-2 synchronous mode was selected from the pin strapping.
If we monitor FREQ_CNT_HIGH it reads 0x00 on start-up when the serializer is powered down.
FREQ_CNT_HIGH changes to 0x14 when the serializer is powered up and LOCK_STS = 1. This would indicate that FREQ_CNT_HIGH 0x14 = 20MHz.
Assuming 40-bit frames, we have 20MHz*40bits = 800Mbps. This is strange since we have set the CSI-2 speed to 400Mbps.
The value of FREQ_CNT_HIGH does not change if we switch between the serializer test pattern register and our image sensor.
Any advice on how we can debug this and get the back channel link running at the correct speed?
