Z8FMC16100 Series Flash MCU
Product Specification
187
STOP—Send Stop Condition
When set, this bit causes the I2C Controller (when configured as the Master) to send the
STOP condition after the byte in the I2C Shift register has completed transmission or after
a byte has been received in a receive operation. When set, this bit is reset by the I2C Con-
troller after a STOP condition has been sent or by deasserting the IENbit. If this bit is 1, it
cannot be cleared to 0 by writing to the register.
If STOP is set while a slave mode transaction is underway, the STOP bit will be cleared by
hardware.
BIRQ—Baud Rate Generator Interrupt Request
This bit is ignored when the I2C Controller is enabled. If this bit is set = 1 when the I2C
Controller is disabled (IEN= 0) the baud rate generator is used as an additional timer caus-
ing an interrupt to occur every time the baud rate generator counts down to one. The baud
rate generator runs continuously in this mode, generating periodic interrupts.
TXI—Enable TDRE interrupts
This bit enables interrupts when the I2C Data register is empty.
NAK—Send NAK
Setting this bit sends a Not Acknowledge condition after the next byte of data has been
received. It is automatically deasserted after the Not Acknowledge is sent or the IENbit is
cleared. If this bit is 1, it cannot be cleared to 0 by writing to the register.
FLUSH—Flush Data
Setting this bit clears the I2C Data register and sets the TDREbit to 1. This bit allows flush-
ing of the I2C Data register when an NAK condition is received after the next data byte
has been written to the I2C Data register. Reading this bit always returns 0.
FILTEN—I2C Signal Filter Enable
Setting this bit enables low-pass digital filters on the SDA and SCL input signals. This
function provides the spike suppression filter required in I2C Fast Mode. These filters
reject any input pulse with periods less than a full system clock cycle. The filters introduce
a 3-system clock cycle latency on the inputs.
I2C Baud Rate High and Low Byte Registers
The I2C Baud Rate High and Low Byte registers, shown in Tables 95 and 96, combine to
form a 16-bit reload value, BRG[15:0], for the I2C Baud Rate Generator. The I2C baud rate
is calculated using the following equation.
Note: If BRG= 0000h, use 10000hin the equation):
System Clock Frequency (Hz)
2
I C Baud Rate (bits/s) =
4 x BRG[15:0]
PS024604-1005
P R E L I M I N A R Y
I2C Baud Rate High and Low Byte Registers
ZILOG [ ZILOG, INC. ]
