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SmartCard Interface Module (SIM)
states in "12x" mode, and 16 states in "16x" mode. Some states simply implement a one RCV_CK delay.
The following states perform additional functions:
RCV16x_1, RCV12x_1
•
— This is the initial state of the receive state machine. If the first bit has not been received, the
state machine remains in this state until a valid start bit is detected. For every subsequent bit,
this state is simply a one RCV_CK cycle delay.
RCV16x_3, RCV12x_2
•
— This state captures the first sample of the current receive data input.
•
RCV16x_7, RCV12x_4
— This state captures the second sample of the current receive data input.
•
RCV16x_8, RCV12x_5
— This state captures the third sample of the current receive data input.
•
RCV16x_9, RCV12x_6
— This state captures the fourth sample of the current receive data input. When the current bit is
the 11th bit of the transfer, this state checks the for valid parity and valid initial character when
appropriate.
— When an error is detected, a NACK is generated in this state when enabled. When the
transmitter is active, the sample captured during this state is the first sample of the NACK
window. This is 0.5 ETU into the 11th bit of the transfer.
•
RCV16x_10, RCV12x_7
— When the current bit is the first bit of a transfer, this state checks the validity of the previous
four samples and perform a majority vote on whether to accept the data as a valid start bit. If
the start bit is valid, the data is shifted into the receive shift register.
— When this is not the first bit of a transfer, this state performs a majority vote on the previous
four samples and places the result in the receive shift register.
•
RCV16x_11, RCV12x_8
— When the current bit is the last bit of the transfer (first stop bit), this state signals the shift
register to place its contents in the receive FIFO. Parity and framing errors are also detected in
this state.
•
RCV16x_13, RCV12x_9
— When the current bit is the last bit of the transfer (first stop bit), this state takes the second
sample of the NACK window.
•
RCV16x_14, RCV12x_10
— When the current bit is the last bit of the transfer (first stop bit), this state takes the third sample
of the NACK window.
•
RCV16x_15, RCV12x_11
— When the current bit is the last bit of the transfer (first stop bit), this state takes the fourth sample
of the NACK window.
•
RCV16x_16, RCV12x_12
— This state represents the end of the current receive input bit. This state increments the bit
counter, performs a majority vote on the NACK samples, and notifies the transmitter when a
NACK pulse was detected.
25-10
MC9328MX1 Reference Manual
MOTOROLA
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