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PIC18F2420 I2C
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: 2008/11/18 22:19 最後登入時間
: 2009/10/28 9:40
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Level : 1 HP : 0 / 21 MP : 3 / 1006 EXP : 86
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請問一下,我用pic18f2420的GPIO去拉H/L 來實現I2C 不是用內建的I2C function. 用的pin是 RC3=SCL ,RC4=SDA - 我接到一I2C的Slave,可是我發現我的slave回ACK時無法將我用4.7K PULL up到3.3v的high level給完全拉到GND,有往下拉,但只有往下拉一點點而已 -- Orz
導至我主程式在判斷ACK時錯誤(認定HIGH LEVEL), 我有試著把PULL UP的電阻拿掉,但也是一樣...
雖然我後來不判斷ACK,我的SLAVE也能Work 但如果我要讀值回來,就只能讀到FF.
請問這是為什麼?? 是軟體設定要修改還是硬體要做修正... 感謝各位。
發表於: 2009/2/7 16:07
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