AT83EB5114 Atmel Corporation, AT83EB5114 Datasheet - Page 27

• Manufacturer Part Number: AT83EB5114
• Manufacturer: Atmel Corporation

Specifications of AT83EB5114

• Max. Operating Frequency: 24 MHz
• Cpu: 8051-12C
• Max I/o Pins: 11
• Adc Channels: 6
• Adc Resolution (bits): 10
• Adc Speed (ksps): 50
• Sram (kbytes): 0.25
• Eeprom (bytes): 256
• Operating Voltage (vcc): 3.0 to 3.6
• Timers: 4
• Mask Rom (kbytes): 4
• Watchdog: Yes

Mode 0 (13-bit Timer)
Mode 1 (16-bit Timer)
Mode 2 (8-bit Timer with Auto-
Reload)
Mode 3 (Halt)
4311C–8051–02/08
•
•
•
•
Mode 0 configures Timer 1 as a 13-bit Timer, which is set up as an 8-bit Timer (TH1 reg-
ister) with a modulo-32 prescaler implemented with the lower 5 bits of the TL1 register
(see Figure 7). The upper 3 bits of TL1 register are indeterminate and should be
ignored. Prescaler overflow increments the TH1 register.
Mode 1 configures Timer 1 as a 16-bit Timer with TH1 and TL1 registers connected in
cascade (see Figure 8). The selected input increments the TL1 register.
Mode 2 configures Timer 1 as an 8-bit Timer (TL1 register) with automatic reload from
the TH1 register on overflow (see Figure 9). TL1 overflow sets the TF1 flag in the TCON
register and reloads TL1 with the contents of TH1, which is preset by the software. The
reload leaves TH1 unchanged.
Placing Timer 1 in mode 3 causes it to halt and hold its count. This can be used to halt
Timer 1 when the TR1 run control bit is not available i.e. when Timer 0 is in mode 3.
For normal Timer operation (GATE1= 0), setting TR1 allows TL1 to be incremented
by the selected input. Setting GATE1 and TR1 allows external pin INT1# to control
Timer operation.
Timer 1 overflow (count rolls over from all 1s to all 0s) sets the TF1 flag and
generates an interrupt request.
When Timer 0 is in mode 3, it uses Timer 1’s overflow flag (TF1) and run control bit
(TR1). For this situation, use Timer 1 only for applications that do not require an
interrupt (such as a Baud Rate Generator for the Serial Port) and switch Timer 1 in
and out of mode 3 to turn it off and on.
It is important to stop the Timer/Counter before changing modes.
27