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

CPU- registers

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

page 45 of the manual

register-name	address	description	ro/rw
DPTR	–	data pointer (16-bit)	rw
DPL0	0x82	data pointer 0 low adress (low byte)	rw
DPH0	0x83	data pointer 0 high adress (high byte)	rw
DPL1	0x84	data pointer 1 low adress (low byte)	rw
DPH1	0x85	data pointer 1 high adress (high byte)	rw
DPS	0x86	data pointer select (0 → pointer 1, 1 → pointer 2)	rw

Examples

   ; 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

Memory

page 53 of the manual

register-name	address	description	ro/rw

Examples

FIXME fill that out ;-)

IO- ports

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

page 61 of the manual

register-name	address	description	ro/rw
PORTACFG	0x7f93	0: use port A as io 1: use special function	rw
PORTBCFG	0x7f94	”	”
PORTCCFG	0x7f95	”	”

OEA	0x7f9c	0: input 1: output	rw
OEB	0x7f9d	”	”
OEC	0x7f9e	”	”

PINSA	0x7f99	value of the input latch	ro
PINSB	0x7f9a	”	ro
PINSC	0x7f9b	”	ro

Examples

//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
  */  
}

Timers

there are 3 16-bit timers

page 257 of the manual

register-name	address	description	ro/rw
TCON	0x88	Timer 0/1 control register	rw
TMOD	0x89	mode for Timer 0/1	rw
CKCON	0x8e	Timer 0/1/2 Rate Control	rw

T2CON	0xc8	Timer 2 control register	rw
RCAP2L	0xca	captured TL2	rw
RCAP2H	0xcb	captured TH2	rw
TL2	0xcc	low-byte of Timer 2	rw
TH2	0xcd	high-byte of Timer 2	rw

Timers 0 and 1

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

TMOD

bit	description
7	GATE1, count when GATE1==0: (TR1==1) GATE1==1: (INT1==1) and (TR1==1)
6	C/T1 - Counter Timer select 0: clocked by CLK24/4 or CLK24/12 1: clocked by T1 (on high→low change)

5	M1, mode-select for Timer 1
4	M0, mode-select for Timer 1
	M1	M0	Mode
	0	0	mode 0: 13-bit counter
	0	1	mode 1: 16-bit counter
	1	1	mode 2: 8-bit counter with auto-reload
	1	1	mode 3: two 8-bit counters


3	GATE0, count when GATE0==0: (TR0==1) GATE0==1: (INT0==1) and (TR0==1)
2	C/T0 - Counter/Timer select 0: clocked by CLK24/4 or CLK24/12 1: clocked by T0 (on high→low change)

1	M1 - mode-select for Timer 0
0	M0 - mode-select for Timer 0

TCON

bit	description
7	TF1 - Timer 1 overflow flag (cleared after interrupt handling) 0: ignore overflows 1: count overflows
6	TR1 - Timer 1 run control 0: stop Timer 1 1: run Timer 1
5	TF0 - same as TF1 but for Timer 0
4	TR0 - same as TR1 but for Timer 0

3	IE1 - Interrupt 1 edge detect set after Interrupt 1 occured (cleared after interrupt handling)
2	IT1 - Interrupt 1 type select 0: detect on low level 1: detect after high→low transition
1	IE0 - same as IE1 but for Interrupt 0
0	IT0 - same as IT1 but for Interrupt 0

CKCON

bit	description
5	T2M - Timer 2 clock select 0: clock with CLK24/12 (like normal 8051) 1: clock with CLK24/4
4	T1M - same as T2M but for Timer 1
3	T0M - same as T2M but for Timer 0

Timer 2

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

CKCON2

bit	description
7	TF2 - Timer 2 overflow flag set when overflow from 0xffff and ( (RCLK==0) and (TCLK==0) ) has to be cleared by software
6	EXF2 - Timer 2 external flag set when reload or capture is caused by a high→low transition on T2EX and (EXEN2==1)
5	RCLK - Receive clock flag 0: Timer 1 overflow as receive clock 1: Timer 2 overflow as receive clock
4	TCLK - Transmit clock flag same as RCLK but for transmit clock
3	EXEN2 - Timer 2 external enable 0: ignore external events on T2EX* 1: enable capture or reload
2	TR2 - Timer 2 runt control flag 0: stop Timer 2 1: run Timer 2
1	C/T2 - Counter/Timer select 0: clocked by CLK24/4 or CLK24/12 1: clocked by T2 (on high→low change)
0	CP/RL2 - Capture/reload flag 1 and (EXEN2==1): capture occur on high→low transistions of T2EX 0 and (EXEN2==1): auto-reload on overflow or high→low transistion on T2EX ( (RCLK==1) or (TCLK=1) )==0: ignore CP/RL2 and autoreload after each overflow

Mode Control

TR2	TCLK	RCLK	CP/RL2	Mode
0	X	X	X	Timer 2 stopped
1	1	X	X	Baud rate generator
1	X	1	X	Baud rate generator
1	0	0	0	16-bit timer/counter with auto-reload
1	0	0	1	16-bit timer/counter with capture
X = Don't care

Examples

//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;
...

Serial Interface

page 268 of the manual

I2C

register-name	address	description	ro/rw
I2CS	0x7fa5	I²C Chip-Select	rw
I2DAT	0x7fa6	I²C Data	rw

Interrupts

page 282 of the manual

register-name	address	description	ro/rw
IE	0xa8	Interrupt Enable	rw
IP	0xb8	Interrupt Priority	rw
EICON	0xd8	External Interrupt Control	rw
EIE	0xe8	External Interrupt Enable	rw
EXIF	0x91	External Interrupt Flag	rw

Interrupt name	Source	Vector	Natural Priority
IE0	INT0 Pin	0x0003	1
TF0	Timer 0 Overflow	0x000b	2
IE1	INT1 Pin	0x0013	3
TF1	Timer 1 Overflow	0x001b	4
RI_0 & TI_0	USART0 Rx & Tx	0x0023	5
TF2	Timer 2 Overflow	0x002b	6
Resume	WAKEUP or USB Resume	0x0033	0
RI_1 & TI_1	USART1 Rx & Tx	0x003b	7
USBINT	USB	0x0043	8
PCINT	I₂C Bus	0x004b	9
IE4	INT4 Pin	0x0053	10
IE5	INT5 Pin	0x005b	11
IE6	INT6 Pin	0x0063	12

IE - Interrupt Enable

bit	description
7	EA - global interrupt enable
6	ES1 - enable Serial Port 1 interrupt
5	ET2 - enable Timer 2 interrupt
4	ES0 - enable Serial Port 0 interrupt
3	ET1 - enable Timer 1 interrupt
2	EX1 - enable external interrupt 1
1	ET0 - enable Timer 0 interrupt
0	EX0 - enable external interrupt 0

IP - Interrupt Priority

bit	description
7	Reserved
6	Reserved
5	Reserved
4	PX6 - external interrupt 6
3	PX5 - external interrupt 5
2	PX5 - external interrupt 4
1	PI2C - I²C Bus interrupt
0	PUSB - USB interrupt

EICON - External Interrupt Control

bit	description
7	SMOD1 - Serial Port 1 baud rate doubler enable
6	Reserved
5	ERESI - enable Resume interrupt
4	RESI - Wakeup interrupt flag
3	INT6 - external interrupt 6 flag
2	Reserved
1	Reserved
0	Reserved

EIE - External Interrupt Enable

bit	description
7	Reserved
6	Reserved
5	Reserved
4	EX6 - enable external interrupt 6
3	EX5 - enable external interrupt 5
2	EX5 - enable external interrupt 4
1	EI2C - enable I²C Bus interrupt
0	EUSB - enable USB interrupt

EXIF - External Interrupt Flag

bit	description
7	IE5 - external interrupt 5 flag
6	IE4 - external interrupt 4 flag
5	I2CINT - I²C interrupt flag
4	USBINT - USB interrupt flag
3	Reserved
2	Reserved
1	Reserved
0	Reserved

Examples

file: http://darcs.erazor-zone.de/ezusb/sdcc/blink_example/main.c

#include <8051.h>
 
#include "ezusb_reg_rzr.h"
 
void main(void) {
  /* setup the io-ports */
  PORTBCFG=0x00;
  PORTCCFG=0x00;
  OEB=0xff;
  OEC=0xff;
  // output both to zero
  OUTB=0x00;
  OUTC=0x00;
 
  /* timer setup */
  // Timer 0 is in mode1 (16-bit counter)
  TMOD=0x01;
  // T0M cleared -> CLK24/12
  CKCON=0x00;
  // start Timer 0
  TCON=0x10;
 
  /* interrupts */
  // set EA and ET0
  IE=0x82;
 
  while ( 1 );
}
 
static void timer0_isr(void) interrupt 1 {
  OUTB=0xff-PINSB;
  OUTC=PINSC+1;
}