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ADV7842 and registers “SPA_PORT_A”, “PORT_A_CHECKSUM”

Question asked by Sasa on Jul 10, 2014
Latest reply on Jul 22, 2014 by mattp

ADV7842 I2C Register Maps (UG-206.pdf) on pg.45 (Repiter) show this registers: bits are named “SPA_PORT_A[]”, “PORT_A_CHECKSUM[]”, registers are named (in left column) “SPA_PORT_C_1,2” (0x72, 0x73), “PORT_C_CHECKSUM” (0x7B).



1. Names “SPA_PORT_C_1,2”, “PORT_C_CHECKSUM”, “SPA_PORT_D_1,2”, “PORT_D_CHECKSUM” – it is mistake for ADV7842, it is names of ADV7844: ADV7842.PORT_A = ADV7844.PORT_C and ADV7842.PORT_B = ADV7844.PORT_D. Correct, please, in UG-206.pdf.



2. Registers “SPA_PORT_A” (Repiter.0x72, 0x73), “PORT_A_CHECKSUM” (Repiter.0x7B) not exist in ADV7842 – am I right?  DataSheet state, that SPA (Source Physical Address) and checksum of the E-EDID block with this SPA for PORT_A take place in internal E-EDID memory – not in registers “SPA_PORT_A” and “PORT_A_CHECKSUM”.  ADV7844 don’t have registers “SPA_PORT_A” and “PORT_A_CHECKSUM”.



About SPA location (UG-214.pdf#page185) – full pointer consist from SPA_LOCATION_MSB (0x77[6]) and SPA_LOCATION (0x76[7:0]).