AN2136SC Cypress Semiconductor Corp, AN2136SC Datasheet - Page 179

• Manufacturer Part Number: AN2136SC
• Description: IC MCU 8051 8K RAM 24MHZ 44QFP
• Manufacturer: Cypress Semiconductor Corp
• Series: EZ-USB®r

Specifications of AN2136SC

• Applications: USB Microcontroller
• Core Processor: 8051
• Program Memory Type: ROMless
• Controller Series: AN213x
• Ram Size: 8K x 8
• Interface: I²C, USB
• Number Of I /o: 8
• Voltage - Supply: 3 V ~ 3.6 V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 44-QFP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: 428-1309

2
The two registers that the 8051 uses to control I
C transfers are shown above. In the EZ-
2
USB family, an I
C interrupt request occurs on INT3 whenever the DONE bit (I2CS.0)
2
makes a 0-to-1 transition. This interrupt signals the 8051 that the I
C controller is ready
for another command.
2
The 8051 concludes I
C transfers by setting the STOP bit (I2CS.6). When the STOP con-
2
2
dition has been sent over the I
C bus, the I
C controller resets I2CS.6 to zero. During the
2
time the I
C controller is generating the stop condition, it ignores accesses to the I2CS and
I2DAT registers. The 8051 code should therefore check the STOP bit for zero before writ-
ing new data to I2CS or I2DAT. In the EZ-USB family, it does this by polling the I2CS.6
bit.
Page 9-16
Chapter 9. EZ-USB Interrupts
EZ-USB TRM v1.9