CS89712 datasheet(167/170 Pages) CIRRUS

167 / 170 page

CS89712

DS502PP2

167

Appendix B: Boot Code

00000000

uart_boot_base

00000000 E3A0C102

MOV

r12, #HwRegisterBase ; R12 = 0x80000000

00000004

00000004 E3A08201

MOV

r8, #InternalRamBase ; R8 = 0x10000000

00000008 E2889B02

ADD

r9, r8, #ImageSize ; R9 = 0x10000800

0000000C

;;; The remaining code is functionally identical to the 7111 boot code

0000000C

;;; First, initialize HW control of UART

0000000C

0000000C 00000480 Hw_UARTDR1 EQU

0x0480

0000000C

0000000C 000004C0 Hw_UBRLCR1 EQU

0x04c0

0000000C 00000017 Hw_BR9600

EQU

0x00000017 ; 9600 baud divisor = 23

0000000C 0000000B Hw_BR9600_13 EQU

0x0000000b ; 9600 baud divisor = 11

0000000C 00060000 Hw_WRDLEN8 EQU

0x00060000

0000000C

0000000C E3A00C01

MOV

r0, #Hw_UART1EN ; Enable UART

00000010 E58C0100

STR

r0, [r12, #Hw_SYSCON]

00000014

00000014 E28C1D45

ADD

r1, r12, #Hw_SYSFLG2 ; (was LDR, ADD in 7111 code)

00000018 E5917000

LDR

r7, [r1]

; R7 = SYSFLG2

0000001C

0000001C E3170040

TST

r7, #Hw_CKMODE

00000020 13A0000B

MOVNE r0, #Hw_BR9600_13 ; Load 13 MhZ value if bit set

00000024 03A00017

MOVEQ r0, #Hw_BR9600 ; If not set, load other divisor

00000028 E3800806

ORR

r0, r0, #Hw_WRDLEN8 ; Insert 8-bit character mode

0000002C

0000002C E58C04C0

STR

r0, [r12, #Hw_UBRLCR1]

00000030

00000030 0000003C StartFlag EQU

‘<’

00000030 0000003E EndFlag EQU

‘>’

00000030

;;; Send ready signal

00000030 E3A0003C

MOV

r0, #StartFlag

00000034 E58C0480

STR

r0, [r12, #Hw_UARTDR1]

00000038

;;; Receive the data

00000038

;;; Store bytes at R9 address, stop loop when R8 == R9

00000038

;;; Leaves R8 set to 0x10000800

00000038

;;; Wait for byte to be available

00000038

uart_ready_loop

00000038 E59C1140

LDR

r1, [r12, #Hw_SYSFLG] ; Spin, if Rx FIFO is empty

0000003C E3110501

TST

r1, #Hw_URXFE1

00000040 1AFFFFFC

BNE

uart_ready_loop

00000044

;;; Read the data, store it, and accumulate checksum

00000044 E59C0480

LDR

r0, [r12, #Hw_UARTDR1] ; Read data

00000048 E4C80001

STRB

r0, [r8], #1 ; Save it in memory

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