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F282xx/F283xx自身带有I2C模块,但受限于TI的官方例程中使用了fifo,其深度为4,在写EEPROM时,读写地址16位,占了2个字节,最多只留下2个字节存储数据,使用很不方便、实用性也极差。有不少网友在这一块碰壁,甚至逼的没办法使用IO口模拟I2C,放弃使用I2C模块。最近一直在测试28027的I2C模块有所获,可突破发送/接收长度限制(非fifo模式,当然这个长度也要和I2C器件匹)。本查介绍查询方式下的I2C模块使。% O( v* c) T7 i6 N) l
1、宏定义I2C模块操作参数
( e+ Z/ [( C1 n#define I2C_SLAVE_ADDR 0x50 //器件地址不含读写位。以24Cxx系列为例,器件地址应为:(0xA0>>1),即0x50
( s1 x8 j: {8 Y#define I2C_NUMBYTES 10 //发送/接收数据长度
4 z. ~' Q9 k( c5 C+ c) X" I+ J" [#define I2C_EEPROM_HIGH_ADDR 0x00
8 l1 ~- x1 I, B; h* t' o" U#define I2C_EEPROM_LOW_ADDR 0x00
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( a3 F/ a) {( d' M2、设置相应GPIO引脚用作I2C引脚。 修改F2802x_I2C.c文件中的void InitI2CGpio()函数。& y$ z* S9 c5 Y5 X
3、初始化I2C模块。# k$ @7 ?1 w/ n$ e
void I2CA_Init(void)
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3 P) d& _+ D$ V$ h2 x( q) e // Initialize I2C
" s7 [$ A' K1 Q0 n; ~ |( z0 I I2caRegs.I2CSAR = 0x0050; // Slave address - EEPROM control code# \9 [0 @- t: H9 {( o) ]; \
* j( ^2 o x9 j5 O! j' c, N // I2CCLK = SYSCLK/(I2CPSC+1)
( P7 G1 ?, D6 n/ I& G% R #if (CPU_FRQ_40MHZ||CPU_FRQ_50MHZ)
: G' x, L1 S- y I2caRegs.I2CPSC.all = 4; // Prescaler - need 7-12 Mhz on module clk+ p* F* x6 D1 E5 O, I; k
#endif
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#if (CPU_FRQ_60MHZ)# ?( \- `6 r4 }5 I% H6 C
I2caRegs.I2CPSC.all = 6; // Prescaler - need 7-12 Mhz on module clk
4 k) b( ]; f6 M- J8 Y+ d& h V" Q #endif
4 m8 ]+ M6 q' }2 }' {& N$ _* ]: t I2caRegs.I2CCLKL = 10; // NOTE: must be non zero+ [$ }6 q' x4 Q) `0 @
I2caRegs.I2CCLKH = 5; // NOTE: must be non zero7 @5 }; V& V; N3 X9 K+ f
I2caRegs.I2CIER.all = 0x00; // Enable SCD & ARDY interrupts
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: v) D4 @; O0 M% d; ~ I2caRegs.I2CMDR.all = 0x0020; // Take I2C out of reset: }6 ]. P6 O. L' H( H4 z! [
// Stop I2C when suspended. ]& K# ?: p% M/ c& z- w
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I2caRegs.I2CFFTX.all = 0x0000; // Enable FIFO mode and TXFIFO6 o" c1 W6 I1 [9 O( g: W
I2caRegs.I2CFFRX.all = 0x0000; // Enable RXFIFO, clear RXFFINT,5 ]0 [5 z. l) ^
3 C5 G& M' Y, a7 h# H$ i7 i return;" ]& B! Q9 M! F, p* q
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4、执行I2C模块接收或者发送。# |6 s: g9 E8 _: K+ B
//I2C模块发送数据到I2C器件。
9 e+ @* h" s! F$ Q; }+ kvoid I2CA_SendData(void). f" W' z4 i% B: Q
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Uint16 i;) A9 |. ]* K* M
I2caRegs.I2CSAR = I2C_SLAVE_ADDR; //Set slave address1 P B* m& F7 \) @7 {. {
I2caRegs.I2CCNT = I2C_NUMBYTES + 2; //Set count to 5 characters plus 2 address bytes
" O9 `) i& f: T/ X I2caRegs.I2CDXR = I2C_EEPROM_HIGH_ADDR; //Send eeprom high address- v+ d4 k |; ?( S8 ~
I2caRegs.I2CMDR.bit.TRX = 1; //Set to Transmit mode
' ^* ^! G+ D4 e! u I2caRegs.I2CMDR.bit.MST = 1; //Set to Master mode: O0 h1 t9 l! x6 x" J! y
I2caRegs.I2CMDR.bit.FREE = 1; //Run in FREE mode
1 U+ ^* Q. J3 Y/ C I2caRegs.I2CMDR.bit.STP = 1; //Stop when internal counter becomes 0
8 ^( { R! X3 z5 l: I2 w I2caRegs.I2CMDR.bit.STT = 1; //Send the start bit, transmission will follow
; `" a4 k% x: g while(I2caRegs.I2CSTR.bit.XRDY == 0){}; //Do nothing till data is shifted out
+ v* ?; Q- U# ^4 i. U2 a2 U I2caRegs.I2CDXR = I2C_EEPROM_LOW_ADDR; //Send eeprom low address
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D2 D% W' K# |, e/ U for(i = 0; i < I2C_NUMBYTES; i++){: v6 A- d |$ W6 [
while(I2caRegs.I2CSTR.bit.XRDY == 0){}; //Do nothing till data is shifted out$ l! B8 R8 l7 @- Z4 A" H; F
I2caRegs.I2CDXR = TxdData; //Send out the message
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}
1 f, k* R3 V4 D- f% F//I2C模块从I2C器件接收数据。2 p5 [, L- F( P z2 ~, ^9 h
void I2CA_ReceiveData(void)
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8 {4 W3 L2 e! H0 d; S; T5 A- Q- g Uint16 i;
+ `* L3 y7 Y) v8 L I2caRegs.I2CSAR = I2C_SLAVE_ADDR; //Set slave address
0 J M2 q! X( Y) _ I2caRegs.I2CCNT = 2; //Set count to 2 address bytes
+ D' R, E" l- y6 {& s I2caRegs.I2CDXR = I2C_EEPROM_HIGH_ADDR; //Send eeprom high address _- w$ ~+ |$ e% R6 G8 C5 r
I2caRegs.I2CMDR.bit.TRX = 1; //Set to Transmit mode" h0 ~* N) b }: [
I2caRegs.I2CMDR.bit.MST = 1; //Set to Master mode9 U6 v! v' H$ A/ b* O
I2caRegs.I2CMDR.bit.FREE = 1; //Run in FREE mode" a) n: j" }$ m9 T
I2caRegs.I2CMDR.bit.STP = 0; //Dont release the bus after Tx
E) F/ X% r5 v' @0 J7 a I2caRegs.I2CMDR.bit.STT = 1; //Send the start bit, transmission will follow
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while(I2caRegs.I2CSTR.bit.XRDY == 0){}; //Do nothing till data is shifted out
; J# T. u: M8 y6 p5 x I2caRegs.I2CDXR = I2C_EEPROM_LOW_ADDR; //Send eeprom low address
7 ^* v7 e. a' y% x7 t8 d I2caRegs.I2CCNT = I2C_NUMBYTES; //read 5 bytes from eeprom
, l/ \9 K- Y# Z I2caRegs.I2CMDR.bit.TRX = 0; //Set to Recieve mode
/ Y( v" ~5 m7 M, @ I2caRegs.I2CMDR.bit.MST = 1; //Set to Master mode8 m, @( Y1 c! P/ C
I2caRegs.I2CMDR.bit.FREE = 1; //Run in FREE mode
: j; ~% r% R6 |3 L6 T O I2caRegs.I2CMDR.bit.STP = 1; //Stop when internal counter becomes 0
- W" C: ?& P& v" W I2caRegs.I2CMDR.bit.STT = 1; //Repeated start, Reception will follow1 E8 s) V \" J4 Y; A
for(i = 0; i < I2C_NUMBYTES; i++){' j4 K8 V, J+ p0 p$ s: R8 R
while(I2caRegs.I2CSTR.bit.RRDY == 0){}; //I2CDRR not ready to read?' K0 `) J/ `7 u z f! T8 S
RxdData = I2caRegs.I2CDRR;' Q8 U) T: e& b, g
}
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