AN2136SC Cypress Semiconductor Corp, AN2136SC Datasheet - Page 316

• 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

The 12 in the denominator in the above equation can be changed to 4 by setting the T1M bit in
the CKCON SFR. To derive the required TH1 value from a known baud rate (when TM1 = 0),
use the equation:
You can also achieve very low serial port baud rates from Timer 1 by enabling the Timer 1
interrupt, configuring Timer 1 to mode 1, and using the Timer 1 interrupt to initiate a 16-bit
software reload. Table C-10. lists sample reload values for a variety of common serial port
baud rates.
Note that more accurate baud rates are achieved by using Timer 2 as the baud rate generator
(next section).
To use Timer 2 as the baud rate generator, configure Timer 2 in auto-reload mode and set the
TCLK and/or RCLK bits in the T2CON SFR. TCLK selects Timer 2 as the baud rate
generator for the transmitter; RCLK selects Timer 2 as the baud rate generator for the receiver.
The 16-bit reload value for Timer 2 is stored in the RCAP2L and RCA2H SFRs, which makes
the equation for the Timer 2 baud rate:
C - 20
Table C-10. Timer 1 Reload Values for Common Serial Port Mode 1 Baud Rates
Settings: SMOD =1, C/T=0, Timer1 mode=2, TIM=1
Note: Using rates that are off by 2.3% or more will not work in all
systems.
Nominal
57600
38400
28800
19200
Rate
9600
4800
2400
Appendix C: 8051 Hardware Description
24 MHz
Divisor
156
10
13
20
39
78
6
TH1 =
Reload
Value
EC
FA
D9
F6
F3
B2
64
256 -
Actual
62500
37500
28846
18750
Rate
9615
4807
2403
384 x Baud Rate
2
SMODx
x
CLK24
+0.16%
+0.16%
+0.15%
+.13%
Error
-2.3%
-2.3%
8.5%
EZ-USB TRM v1.9