SAF-C161U-LF V1.3 Infineon Technologies, SAF-C161U-LF V1.3 Datasheet - Page 405

• Manufacturer Part Number: SAF-C161U-LF V1.3
• Description: IC MCU ISDN 16BIT TTL TQFP-100
• Manufacturer: Infineon Technologies
• Series: C16xxr

Specifications of SAF-C161U-LF V1.3

• Core Processor: C166
• Core Size: 16-Bit
• Speed: 36MHz
• Connectivity: EBI/EMI, SPI, UART/USART, USB
• Peripherals: POR, PWM, WDT
• Number Of I /o: 56
• Program Memory Type: ROMless
• Ram Size: 3K x 8
• Voltage - Supply (vcc/vdd): 3 V ~ 3.6 V
• Oscillator Type: External
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 100-LFQFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Program Memory Size: -
• Data Converters: -
• Other names: SAFC161ULFV1.3X; SAFC161ULFV13XP; SP000007502

21.3
To support modular programming a procedure mechanism is provided to allow coding of
frequently used portions of code into subroutines. The CALL and RET instructions store
and restore the value of the instruction pointer (IP) on the system stack before and after
a subroutine is executed.
Procedures may be called conditionally with instructions CALLA or CALLI, or be called
unconditionally using instructions CALLR or CALLS.
Note: Any data pushed onto the system stack during execution of the subroutine must
Passing Parameters on the System Stack
Parameters may be passed via the system stack through PUSH instructions before the
subroutine is called, and POP instructions during execution of the subroutine. Base plus
offset indirect addressing also permits access to parameters without popping these
parameters from the stack during execution of the subroutine. Indirect addressing
provides a mechanism of accessing data referenced by data pointers, which are passed
to the subroutine.
In addition, two instructions have been implemented to allow one parameter to be
passed on the system stack without additional software overhead.
The PCALL (push and call) instruction first pushes the 'reg' operand and the IP contents
onto the system stack and then passes control to the subroutine specified by the 'caddr'
operand.
When exiting from the subroutine, the RETP (return and pop) instruction first pops the IP
and then the 'reg' operand from the system stack and returns to the calling program.
Cross Segment Subroutine Calls
Calls to subroutines in different segments require the use of the CALLS (call inter-
segment subroutine) instruction. This instruction preserves both the CSP (code segment
pointer) and IP on the system stack.
Upon return from the subroutine, a RETS (return from inter-segment subroutine)
instruction must be used to restore both the CSP and IP. This ensures that the next
instruction after the CALLS instruction is fetched from the correct segment.
Note: It is possible to use CALLS within the same segment, but still two words of the
Providing Local Registers for Subroutines
For subroutines which require local storage, the following methods are provided:
Data Sheet
be popped before the RET instruction is executed.
stack are used to store both the IP and CSP.
Procedure Call Entry and Exit
405
System Programming
2001-04-19
C161U