Tool/software:
In some cases, i2c scl signal measured shown 100Khz when Local slave proxy Ti960 I2C set fast plus mode (1Mhz), remote mast proxy ti953 i2c set fast plus mode(1Mhz).
case 1. Just connect ti960 to host processor, i2c controller of host controller set i2c speed fast plus (1Mhz), i2c analyzer measured shown as expected, 1Mhz.
but when plugin ti953, i2c analyzer shown i2c SCL reduced to 100Khz, no matter ti953 I2c speed set standard/fast/fast-plus.
case2. For some deug reasons, we read back ti953 register value just after set, and RESET_CTL Register (Address 0x01) reset ti953, need 3ms delay for i2c access, so
a bug when we directly read back , i2c read failed. And this behavior also casued i2c scl signal shown 100Khz, even we set Local slave proxy Ti960 I2C set fast plus mode (1Mhz),
remote mast proxy ti953 i2c set fast plus mode(1Mhz). (we checked ti953 register, scl high time, 0xb = 0x6, scl low time 0xc 0xb.)
e.g 1
Ti953 fast-plus , ti960 fast-plus, serdes i2c debug Disabled
SCL 1Mhz
SCL clock stretch 14.125 us
e.g 2
Ti953 fast-plus , ti960 fast-plus, serdes i2c debug Enabled
SCL 100Khz
SCL clock stretch 18 us
...