SX User’s Manual Rev. 3.1 30 © 2000 Scenix Semiconductor, Inc. All rights reserved. www.scenix.com Chapter 2 Architecture Table 2-2  Register Summary Register Name Description W Working Register. This is the main working register used by many instructions
as the source or destination of the operation. INDF (00h) Indirect through FSR. There is no actual register at this memory location. When
this address (00h) is specified as the source or destination of an operation, the
register location pointed to by FSR is accessed. RTCC (01h) Real-Time Clock/Counter. This register can be used to keep track of elapsed
time or occurrences of transitions on the RTCC input pin. PC (02h) Program Counter. Only the lower eight bits of the program counter are available
at this register location. STATUS (03h) Status. This register contains the status bits for the device such as the C bit, Z
bit, and program memory page selection bits. FSR (04h) File Select Register. This register specifies the bank number for direct address-
ing or the full 8-bit address for indirect addressing. RA (05h) Port A Data Register. This register is used to control output signals and read
input signals on the RA0-RA7 I/O pins. RB (06h) Port B Data Register. This register is used to control output signals and read
input signals on the RB0-RB7 I/O pins. RC (07h) Port C Data Register. This register is used to control output signals and read
input signals on the RC0-RC7 I/O pins. In devices without Port C, the register at
07h is a general-purpose register. RD (08h) Port D Data Register. This register is used to control output signals and read
input signals on the RD0-RD7 I/O pins. In devices without Port D, the register
at 08h is a general-purpose register. RE (09h) Port E Data Register. This register is used to control output signals and read
input signals on the RE0-RE7 I/O pins. In devices without Port E, the register at
09h is a general-purpose register. Port Control Registers The port control registers are used to control the configuration of the port I/O
pins. These registers are accessed by a special-purpose instruction, “mov !rx,W”. MODE MODE Register. This register controls access to the port control registers when
you use the “mov !rx,W” instruction. OPTION Option Register. This register sets some device configuration options such as
the Real-Time Clock/Counter incrementing mode.