Cypress PSoC CY8CTMG20 Series, Техническое справочное руководство

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32 PSoC CY8CTMG20x and CY8CTST200 TRM, Document No. 001-53603 Rev. *C
CPU Core (M8C)
2.6 Register Definitions
The following register is associated with the CPU Core (M8C). The register description has an associated register table show-
ing the bit structure. The bits that are grayed out in the table are reserved bits and are not detailed in the register description
that follows. Always write reserved bits with a value of ‘0’.
2.6.1 CPU_F Register
The M8C Flag Register (CPU_F) provides read access to
the M8C flags.
Bits 7 and 6: PgMode[1:0]. PgMode determines how the
CUR_PP, STK_PP, and IDX_PP registers are used in form-
ing effective RAM addresses for Direct Address mode and
Indexed Address mode operands. PgMode also determines
whether the stack page is determined by the STK_PP or
IDX_PP register. (See the
Register Definitions on page 42 in
the RAM Paging chapter.)
Bit 4: XIO. The I/O bank select bit, also known as the regis-
ter bank select bit, is used to select the register bank that is
active for a register read or write. This bit allows the PSoC
device to have 512 8-bit registers and is thought of as the
ninth address bit for registers. The address space accessed
when the XIO bit is set to ‘0’ is called
user space , while
address space accessed when the XIO bit is set to ‘1‘ is
called
configuration space .
Bit 2: Carry. The Carry flag bit is set or cleared in response
to the result of several instructions. It is also manipulated by
the flag logic opcodes (for example, OR F, 4). See the PSoC
Designer Assembly Language User Guide for more details.
Bit 1: Zero. The Zero flag bit is set or cleared in response
to the result of several instructions. It is also manipulated by
the flag logic opcodes (for example, OR F, 2). See the
PSoC
Designer Assembly Language User Guide for more details.
Bit 0: GIE. The state of the Global Interrupt Enable bit
determines whether interrupts (by way of the interrupt
request (IRQ)) are recognized by the M8C. This bit is set or
cleared using the flag logic instructions (for example, OR F,
1). GIE is also automatically cleared when an interrupt is
processed, after the flag byte has been stored on the stack,
preventing nested interrupts. If wanted, set the bit in an
interrupt service routine (ISR) . For GIE=1, the M8C sam-
ples the IRQ input for each instruction. For GIE=0, the M8C
ignores the IRQ.
For additional information, refer to the CPU_F register on
page 254 .
2.6.2 Related Registers
The following registers are related to the M8C block:
■
CPU_SCR1 register on page 257 .
■
CPU_SCR0 register on page 258 .
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Access
x,F7h CPU_F PgMode[1:0] XIO Carry Zero GIE RL : 02
LEGEND
L The AND F, expr; OR F, expr; and XOR F, expr flag instructions can be used to modify this register.
x An “x” before the comma in the address field indicates that this register can be read or written to no matter what bank is used.
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