Maxim-integrated MAXQ622 Bedienungsanleitung PDF herunterladen (Seite 187)

MAXQ612/MAXQ622 User’s Guide

Maxim Integrated 12-17

12.5.2 USB Example 2: Writing to an Internal USB Register (EP2BC)

To write to the USB state registers, the user will write the destination register offset to UADDR, write data to UDATA

;; writing to USB register

MOV UADDR, #EP2BC ; Read EP2BC register, #EP2BC = 12h

; (RW=0, ADDR=10010

MOV UDATA, #0010h ; Write 0010h to the EP2BC register

CHK: MOV C, UADDR.6 ; Loop to check UBUSY flag

JUMP NC, CHK ; and wait for it to clear

Figure 12-5. Writing to an Internal USB Register

CPU_CLK

CPU WRITE

REG_ADDR1

CPU WRITE

UDATA1

SET UBUSY = 1

CPU READS

UBUSY = 0CPU WAIT

UADDR[4:0]

UDATA[7:0]

USBRW

UBUSY

SIE_CLK

SIE_DATA[7:0]

SIE_UBUSY

REG_ADDR1

UDATA1

CLEARS CPU UBUSY

SIE WRITES

UDATA1

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Maxim-integrated MAXQ622 Bedienungsanleitung Seite 187