ADuC831,电子系统设计--FLASH.ppt

It should be noted that a given mode of operation is initiated as soon as the command word is written to the ECON SFR. The core microcontroller operation on the ADuC831 is idled until the requested Program/Read or Erase mode is completed. This means that even though the Flash/EE memory mode of operation is typically initiated with a two-machine cycle MOV instruction (to write to the ECON SFR), the next instruction will not be executed until the Flash/EE operation is complete. This means that the core will not respond to interrupt requests until the Flash/EE operation is complete, although the core peripheral functions like counter/timers will continue to count and time as configured throughout this period. 电子设计专题——AD?C831系统资源介绍3 AD?C831系统资源介绍3 ——NONVOLATILE FLASH/ee MEMORY Timer 3 Generated Baud Rates TIC Control Register AD?C831 NONVOLATILE FLASH/ee MEMORY概述 AD?C831 Flash/EE Program Memory Timer 1 Generated Baud Rates Modes1 and 3 Baud Rate = (2SMOD /32) ×( Core Clock / (12×[256 – TH1])) Timer 2 Generated Baud Rates Modes 1 and 3 Baud Rate =(Core Clk)/( 32 ×[65536 – (RCAP2H, RCAP2L)]) Timer 3 Generated Baud Rates MCS-51 using a 12 MHz crystal, a baud rate of 115200 is not possible. To address this problem, the ADuC831 has added a dedicated baud rate timer (Timer 3) specifically for generating highly accurate baud rates. Timer 3 can be used instead of Timer 1 or Timer 2 for generating very accurate high speed UART baud rates including 115200 and 230400. Timer 3 also allows a much wider range of baud rates to be obtained. In fact, every desired bit rate from 12 bit/s to 393216 bit/s can be generated to within an error of ±0.8%. Two SFRs (T3CON and T3FD) are used to control Timer 3.T3CON is the baud rate control SFR, allowing Timer 3 to be used to set up the UART baud rate, and setting up the binary divider (DIV). T3FD is the fractional divider ratio required to achieve the required baud rate. T3CON SFR Bit 地址 位7 位6 位5 位4 位3 位2 位1 位0 9EH T3BAUDEN D