JZ2440 Light an LED

LED labeled D10, its corresponding Gpio is GPF4, that is, set GPF4 for output, and pull low to low level "specific principle view JZ2440 schematic"

1 #defineGpfcon (* (volatile unsigned long *) 0x56000050)2 #defineGpfdat (* (volatile unsigned long *) 0x56000054)3 4 #defineGpf4_o (1<< (4*2))5 6 intMain ()7 {8     //set GPF4 to output IO9Gpfcon =Gpf4_o;Ten     //pull the GPF output all high OneGpfdat =0XFF; A      -      while(1){ -         //set the GPF4 output to a low level theGpfdat &= ~ (1<<4); -     } -  -     return 0; +}

As a result of the experiment, inadvertently found that the GPF output defaults to low level, that is, set GPF4 for export, do not set the level, LED will also light, so in order to achieve experimental results, in the 11th row gpf all IO port pull high.

JZ2440 lit an LED