P89C660 View Datasheet(PDF) - Philips Electronics
Part Name
Description
Manufacturer
P89C660 Datasheet PDF : 89 Pages
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Philips Semiconductors
80C51 8-bit Flash microcontroller family
16KB/32KB/64KB ISP/IAP Flash with 512B/1KB/2KB/8KB RAM
Product data
P89C660/P89C662/P89C664/
P89C668
SDA
INTERNAL BUS
8
BSD7
S1DAT
ACK
SCL
SHIFT PULSES
SU00969
Figure 6. Serial Input/Output Configuration
SDA
D7
D6
D5
D4
D3
D2
D1
D0
A
SCL
SHIFT ACK & S1DAT
ACK
(2)
(2)
(2)
(2)
(2)
(2)
(2)
(2)
A
SHIFT IN
S1DAT
(1)
(2)
(2)
(2)
(2)
(2)
(2)
(2)
(2)
(1)
SHIFT BSD7
BSD7
D7
D6
D5
D4
D3
D2
D1
D0
(3)
SHIFT OUT
LOADED BY THE CPU
(1) Valid data in S1DAT
(2) Shifting data in S1DAT and ACK
(3) High level on SDA
Figure 7. Shift-in and Shift-out Timing
SU00970
In the following text, it is assumed that ENS1 = “1”.
The “START” Flag, STA: STA = “1”: When the STA bit is set to
enter a Master mode, the SIO1 hardware checks the status of the
I2C bus and generates a START condition if the bus is free. If the
bus is not free, then SIO1 waits for a STOP condition (which will free
the bus) and generates a START condition after a delay of half a
clock period of the internal serial clock generator.
If STA is set while SIO1 is already in a Master mode and one or
more bytes are transmitted or received, SIO1 transmits a repeated
START condition. STA may be set at any time. STA may also be set
when SIO1 is an addressed slave.
STA = “0”: When the STA bit is reset, no START condition or
repeated START condition will be generated.
The STOP Flag, STO: STO = “1”: When the STO bit is set while
SIO1 is in a Master mode, a STOP condition is transmitted to the
I2C bus. When the STOP condition is detected on the bus, the SIO1
hardware clears the STO flag. In a Slave mode, the STO flag may
be set to recover from an error condition. In this case, no STOP
condition is transmitted to the I2C bus. However, the SIO1 hardware
behaves as if a STOP condition has been received and switches to
the defined “not addressed” Slave Receiver mode. The STO flag is
automatically cleared by hardware.
2002 Oct 28
17
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