upd70f3402 Renesas Electronics Corporation., upd70f3402 Datasheet - Page 71

• Manufacturer Part Number: upd70f3402
• Description: 32-/16-bit Single-chip Microcontroller With Can Interface
• Manufacturer: Renesas Electronics Corporation.

(1)
<1> Disable DMA operation.
<2> Prepare data to be set to the special register in a general-purpose register.
<3> Write the data prepared in <2> to the command register (PRCMD).
<4> Write the setting data to the special register (by using the following instructions).
<5> to <9> Insert NOP instructions (5 instructions).
<10> Enable DMA operation if necessary.
Cautions: 1. When a store instruction is executed to store data in the command register, inter-
Setting data to special registers
Set data to the special registers in the following sequence.
• Store instruction (ST/SST instruction)
• Bit manipulation instruction (SET1/CLR1/NOT1 instruction)
[Example] With PSC register
<1>
<2>
<3>
<4>
<5>
<6>
<7>
<8>
<9>
<10> SET1 0, DCHCn[r0]; Enable DMA operation. n = 0 to 5
(next instruction)
There is no special sequence to read a special register.
ST.B
CLR1 0, DCHCn[r0]
MOV
ST.B
ST.B
NOP; Dummy instruction
NOP; Dummy instruction
NOP; Dummy instruction
NOP; Dummy instruction
NOP; Dummy instruction
2. Although dummy data is written to the PRCMD register, use the same general-
3. Five NOP instructions or more must be inserted immediately after setting the
rupts are not acknowledged. This is because it is assumed that steps <3> and <4>
above are performed by successive store instructions. If another instruction is
placed between <3> and <4>, and if an interrupt is acknowledged by that instruc-
tion, the above sequence may not be established, causing malfunction and an
error to be stored in the PERR bit of the SYS register.
purpose register used to set the special register (<4> in Example) to write data to
the PRCMD register (<3> in Example). The same applies when a general-purpose
register is used for addressing.
IDLE mode or software STOP mode (by setting the STP bit of the PSC register
to 1).
r11, PSMR[r0]
0x02, r10
r10, PRCMD[r0]
r10, PSC[r0]
User’s Manual U16702EE3V2UD00
Chapter 3 CPU Function
; Set PSMR register.
; Disable DMA operation. n = 0 to 5
; Write PRCMD register.
; Set PSC register.
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