EZ-USB summary

compared to the normal 8051 core:

• 4 clocks for 1 bus-cycle
• 24MHz clock (with a 12Mhz resonator)
• a second data pointer
• a second UART
• a third 16-bit timer
• a high-speed memory interface with a non-multiplexed 16-bit address bus
• 8 additional interrupts
• variable movex timing
• 3.3V operation

these are in the SFR- of the core (8-bit- address), most of them are handled via the compiler

• page 45 of the manual

   ; assembly example
   ; set the first data pointer to 0x000a
   mov DPTR, #0x000ah
   ; select the second data pointer
   inc DPS
   ;set the second data pointer to 0x100a
   mov DPTR, #0x100ah

• page 53 of the manual

fill that out

these are located in the external RAM (16-bit- Address)

• page 61 of the manual

//C example 1, simple assignments
void main(void) {
  // port A and B are simple IO's (all bits are cleared)
  PORTACFG=0x00;
  PORTBCFG=0x00;
 
  // port A is input only
  OEA=0x00;
 
  // port B is input too but the first 4 bits are outputs
  OEB=0x0f;
 
  // the first 4 bits of B getting the same value as the coresponding inputs of A
  // the last 4 bits are of no interest
  OUTB=PINSA;
}

//C example 2, wrong and right assignments
void main(void) {
  // port A as IO's (all bits are cleared)
  PORTBCFG=0x00;
 
  // port A is output only
  OEB=0xff;
 
  // wrong assignment
  OUTC=PINSC++; // (same as PINSC=PINSC+1; OUTC=PINSC;)
  /* a short explanation why thats wrong
     the compiler would produce the following:
    C: PINSC=PINSC+1;
  ASM:    
       mov  DPTR,#PINSC
       movx a,@DPTR  ;loading PINSC to a
       inc a
       movx @DPTR,a  ;writing a to PINSC will be ignored
 
    C: OUTC=PINSC;
  ASM:
       mov  DPTR,#PINSC
       movx a,@DPTR  ;loading PINSC to a
       mov  DPTR,#OUTC
       movx @DPTR,a  ;writing a to OUTC
  */  
 
  // right assignment
  OUTC=PINSC+1;
  /* 
    C: PINSC+1;
  ASM:    
       mov  DPTR,#PINSC
       movx a,@DPTR  ;loading PINSC to a
       add a,#0x01   ;add 1
 
    C: OUTC=...;
  ASM:
       mov  DPTR,#OUTC
       movx @DPTR,a  ;writing a to OUTC
  */  
}

there are 3 16-bit timers

• page 257 of the manual

• page 258 of the manual
• 4 modes:
  • mode0: 13-bit timer/counter
    • uses bits 0-4 of TL0/TL1 and all 8 of TH0/TH1
  • mode1: 16-bit timer/counter
  • mode2: 8-bit counter with auto-reload
  • mode3: two 8-bit counters (Timer 0 only)
    • Timer 0 uses TR1 and TF1
    • limits the usage of Timer 1

• page 264 of the manual
• 4 modes:
  • mode0: 16-bit timer/counter
  • mode1: 16-bit timer/counter with capture
  • mode2: 16-bit counter with auto-reload
  • mode3: baud rate generator
    • T2M ignored

//C example 1, simple setup of Timer 0
...
  /* timer setup */
  // Timer 0 is in mode1 (16-bit counter)
  TMOD=0x01;
  // T0M cleared -> CLK24/10
  CKCON=0x00;
  // start Timer 0
  TCON=0x10;
...

• page 268 of the manual

• page 282 of the manual