AT89C5132 Atmel Corporation, AT89C5132 Datasheet - Page 148

• Manufacturer Part Number: AT89C5132
• Manufacturer: Atmel Corporation

Specifications of AT89C5132

• Flash (kbytes): 64 Kbytes
• Max. Operating Frequency: 20 MHz
• Cpu: 8051-12C
• Max I/o Pins: 44
• Usb Transceiver: 1
• Usb Speed: Full Speed
• Usb Interface: Device
• Spi: 1
• Uart: 1
• Adc Channels: 2
• Adc Resolution (bits): 10
• Adc Speed (ksps): 22.7
• Sram (kbytes): 2.25
• Self Program Memory: API
• Operating Voltage (vcc): 2.7 to 3.6
• Timers: 2
• Isp: UART/USB
• Watchdog: Yes

21.1.1
21.1.2
21.1.3
148
AT89C5132
Clock Generator
Channel Selection
Conversion Precision
Figure 21-2. Timing Diagram
The ADC clock is generated by division of the peripheral clock (see details in Section “X2 Fea-
ture”, page 12). The division factor is then given by ADCP4:0 bits in ADCLK register. Figure 21-
3 shows the ADC clock generator and its calculation formula
Figure 21-3. ADC Clock Generator and Symbol Caution:
Note:
The channel on which conversion is performed is selected by the ADCS bit in ADCON register
according to Table 30.
Table 30. ADC Channel Selection
The 10-bit precision conversion is achieved by stopping the CPU core activity during conversion
for limiting the digital noise induced by the core. This mode called the Pseudo-Idle mode
enabled by setting the ADIDL bit in ADCON register
Section "Conversion Launching", page 149), the CPU core is stopped until the end of the con-
1. In all cases, the ADC clock frequency may be higher than the maximum F
2. The ADCD value of 0 is equivalent to an ADCD value of 32.
ADEOC
ADSST
CLOCK
ADEN
reported in the Section “Analog to Digital Converter”, page 201.
PER
CLK
ADCS
T
0
1
÷ 2
SETUP
T
ADCD4:0
ADCLK
ADCLK
ADCclk
=
(3)
-------------------------
2 ADCD
PERclk
⋅
. Thus, when conversion is launched (see
T
ADC Clock
CONV
(1)
.
Channel
AIN1
AIN0
ADC Clock Symbol
CLOCK
ADCLK
ADC
4173E–USB–09/07
parameter
(1),(2)
is