TSC695F
Timers
In software debug mode the timers are controlled by a system register bit and the exter-
nal pin DEBUG.
General Purpose Timer
The General Purpose Timer (GPT) provides, in addition to a generalized counter func-
tion, a mechanism for setting the step size in which actual time counts are performed.
GPT is clocked by the internal system clock. They are possible to program to be either
of single-shot type or periodical type and in both cases generate an interrupt when the
delay time has elapsed. The current value of the scaler and counter of the GPT can be
read.
Real Time Clock Timer
Watchdog Timer
The only functional differences between the two timers are that the Real Time Clock
Timer (RTCT) has an 8-bit scaler (16-bit scaler for GPT) and that the RTCT interrupt has
higher priority than the GPT interrupt.
RTCT information is available on RTC output pin.
Setting the external pin IWDE to VCC enables the internal watchdog timer. Otherwise the
watchdog function must be externally provided.
The watchdog is supplied from a separate external input (WDCLK). After reset, the timer
is enabled and starts running with the maximum range. If the timer is not refreshed
(reprogrammed) before the counter reaches zero value, an interrupt is sent. Simulta-
neously, the timer starts counting a reset time-out period. If the timer is not
acknowledged before the reset time-out period elapses, a reset is applied to TSC695F.
UARTs
Two full duplex asynchronous receiver transmitters (UART) are included. In software
debug mode the UART’s are controlled by system register bits.
The data format of the UART’s is eight bits. It is possible to choose between even or odd
parity, or no parity, and between one and two stop bits. The UART’s provide double buff-
ering, i.e. each UART consists of a transmitter holding register, a receiver holding
register, a transmitter shift register, and a receiver shift register. Each of these registers
are 8-bit wide. For each UART a RX and TX Register is provided. The UART’s generate
an interrupt each time a byte has been received or a byte has been sent. There is
another interrupt to indicate errors.
The baud rate of both the UART’s is programmable. The clock is derived either from the
system clock or can use the watchdog clock.
General Purpose Interface
The General Purpose Interface (GPI) is an 8-bit parallel I/O port. Each pin can be config-
ured as an input or an output.
A falling or rising edge detection is made on each selected GPI inputs. Every input tran-
sition on GPI generates an external positive pulse on GPIINT pin of two SYSCLK width.
Execution Modes
Reset Mode
Reset mode is entered when:
–
–
The SYSRES input is asserted
Software reset which is caused by the software writing to a Software Reset
Register
–
–
Watchdog reset which is caused by a Watchdog counter time-out
Error reset which is caused by a hardware parity error
11
4118H–AERO–06/03
ATMEL [ ATMEL ]
