UPSD3422_06 Datasheet, PDF (132/293 Pages) STMicroelectronics – Turbo Plus Series Fast Turbo 8032 MCU with USB and Programmable Logic

I²C interface
uPSD34xx
Is this the next to last byte to receive from Slave?
If this is the next to last byte, do not allow Master to ACK
on next interrupt.
– S1CON.AA = 0, don’t let Master return ACK
– Exit ISR, now ready to recv last byte from Slv
If this is not next to last byte, let Master send ACK to
Slave
<S1CON.AA is already 1>
– Exit ISR, ready to recv more bytes from Slave
Else If mode is Slave-Transmitter:
Is this Intr from SIOE detecting a STOP on bus?
If Yes, a STOP was detected:
– S1DAT = dummy, write to release bus
– Exit ISR, Master needs no more data bytes
If No, a STOP was not detected, continue:
ACK recvd from Master? (status.ACK_RESP=0?)
If No, an ACK was not received:
– S1DAT = dummy, write to release bus
– Exit ISR, Master needs no more data bytes
If Yes, ACK was received, then continue:
– S1DAT = xmit_buf[buffer_index], transmit byte
– Exit ISR, transmit next byte on next interrupt
Else If mode is Slave-Receiver:
Is this Intr from SIOE detecting a STOP on bus?
If Yes, a STOP was detected:
– recv_buf[buffer_index] = S1DAT, get last byte
– Exit ISR, Master has sent last byte
If No, a STOP was not detected, continue:
Determine if this Interrupt is from receiving an address or a data
byte from a Master.
Is (S1CON.ADDR = 1 and S1CON.AA =1)?
If No, intr is from receiving data, goto C:
If Yes, intr is from an address, continue:
– slave_is_adressed = 1, local variable set true
<indicates Master selected this slave>
– S1CON.ADDR = 0, clear address match flag
Determine if R/W bit indicates transmit or receive.
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