SN8P275X Series
8-bit micro-controller build-in 12-bit ADC
SONiX TECHNOLOGY CO., LTD
Page 126
Version 0.7
10.7.4 General Call Address
In MSP bus, the first 7-byte is the Slave address. Only the address match MSPADDR the Slave will response an ACK_.
The exception is the general call address which can address all slave devices. When this address occur, all devices
should response an acknowledge.
The general call address is a special address which is reserved as all “0” of 7-bytes address. The general call address
function is control by GCEN bit. Set this bit will enable general call address and clear it will disable. When GECN=1,
following a START signal, 8-bit will shift into MSPSR and the address is compared with MSPADD and also the general
call address which fixed by hardware.
If the genera call address matches, the MSPSR data is transferred into MSPBUF, the BF flag bit is set, and in the
falling edge of the ninth clock (ACK_) MSPIRQ flag set for interrupt request. In the interrupt service routine, reading
MSPBUF can check if the address is the general call address or device specific.
General Call Address Timing Diagram
