Cypress USB教程第5讲

Diagnose the problem Add an ISR for USB Reset Demonstration (suspend2.c)

static void URES_ISR (void) interrupt 04 // '04' is USB bus reset interrupt number { EZUSB_IRQ_CLEAR(); // Always clear INT2 flag first USBIRQ = bmURES; // ...then clear SUSPEND IRQ by writing "1" to IRQ bit display_hex(0xB6); // 3 horiz segments only }
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A solution

Re-arm IN2 whenever there‟s a USB reset
This preserves the data already loaded into the IN endpoint buffer Demonstration

static void URES_ISR (void) interrupt 04 // '04' is USB bus reset interrupt number { EZUSB_IRQ_CLEAR(); // Always clear INT2 flag first USBIRQ = bmURES; // ...then clear SUSPEND IRQ by writing "1" to IRQ bit display_hex(0xB6); // 3 horiz segments only IN2BC=1; // re-arm our IN endpoint }
Get_Descriptor: Device Get_Descriptor: Interface Get_Descriptor: String
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Suspend/Resume
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Suspend-Resume Mechanism (TRM Ch.11)
12 MHz
WAKEUP pin USB RESUME
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What‟s Happening

USB bus reset un-arms all IN endpoints
TRM

page 10-6, Section 10.5:
“After a USB bus reset, the EZ-USB core „unarms‟ all Bulk IN endpoints. Data loaded by the 8051 into an IN endpoint buffer remains there, and the 8051 firmware can either re-send it by loading the endpoint byte count register to re-arm the transfer, or send new data by reloading the IN buffer before re-arming the endpoint.”
USB "SUSPEND" Interrupt
static void Suspend_ISR (void) interrupt 03 5-3
„SuEUP pin USB RESUME
ST ART ST OP
Oscillator
PLL 48 MHz div by 2 CLK24 PCON.0 "RESUME" INT 8051 Signal Resume (USBCS.0)

Set Report, Get Report
You need the spec, and the HID Usage Tables
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Full Spec at

HID

The HID descriptor is in the Interface descriptor, not the Device descriptor

Help/Contents and Tutorial, and Help/Control Panel User Guide

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HID Part 1
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HID Class



Built into Windows 98 (or later) No need to write a driver! Mostly used by mice, keyboards Communicates with devices using reports
3bits5bitshidtools?hiddescriptortool?freeutilityonwwwusborg?helpscreatereportdescriptors?checksforerrors522?checksforerrors?hidview?partofusbcheck?alsoonwwwusborg?testsforusbcomplianceenumerationcode523enumerationlite?startwritingourownenumerationcode?projectssofarhaveusedthepreenumeratedchip?alldescriptorsforthepreenumeratedchiparehardwiredinthesieanddocumentedinthetrm?ezusbhasarenumbitusbcs07fd6bit1524?usbcs0x7fd6bit1?renum0whenthechipcomesoutofreset?intelligentsiehandlesallhostchapter9requests?8051codehandlesdatatransfers?weusedthisfeatureinbulkinandbulkoutassignments?the8051cansetrenum1tohandlecontrolrequestsincode
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„Resume‟
12 MHz
WAKEUP pin USB RESUME
ST ART ST OP
Oscillator
PLL 48 MHz div by 2
Restart Delay
8051 Interrupt 6 (vector 0x33)
PCON.0 "RESUME" INT 8051
CLK24

This table is built from compile of your code (w. includes)

Set WatchPoints
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Watch window updates when code execution stops
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Where to find tools help
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Final Suspend/Resume Note

No apparent consistency from PC to PC in handling suspend
Most variation seen in laptops How (and if) they suspend How (and if) they resume KILLER: Some turn off Vbus during suspend
Restart Delay
8051 does power-saving housekeeping, then sets PCON.0 to turn off oscillator.
No USB activity for 3 msec.
USB "SUSPEND" Interrupt
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„Suspend‟ Code

C:\Cypress\USB\uV2_4k\keil\C51\HLP

A51.pdf is Assembler Reference Manual C51.pdf is C Compiler Reference Manual
C:\Cypress\USB\Doc\Keil Doc EZ-USB Control Panel
Lecture 5 Agenda
Suspend/Resume
How it works How to code it A Gotcha Keil Debug tip—the Watch window
HID Introduction Enumeration code
Start safely Use control panel to test:
suspend.c int2jmp.a51 wuisr.c

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Suspend/Resume Issue

There is a problem with suspend.c
After „resume‟, the next IN-2 request hangs Demonstration

Allows different interfaces to use HID differently (e.g. for different controls)

Class code (in interface descriptor) bInterfaceClass = 3 for HID Report Descriptors


VERY hard to execute „resume‟ code if we are bus-powered and the power goes away…
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Keil Debug Tip
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Keil Debugging Tip

Using the Watch Window

Display all symbols
}
Note: this code MUST be placed in a different module than ‘suspend.c’ code, because ‘suspend.c’ overrides the normal 8051 interrupt vectors with it’s directive: #pragma intvector (0x17FD)
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„Resume‟ Code


Complete example in „suspend.c‟ sofint.c with enhancements: Updates digit count rate from EP2OUT Adds suspend/resume code Three code modules
(Initialization in „main()‟: USBIEN = bmSOF | bmSUSP; EICON |= 0x20; // Enable SOF & --- Suspend interrupts // *** Enable Resume Interrupt // '03' is SUSPEND interrupt number
USB "SUSPEND" Interrupt
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„Resume‟ Code
// wuisr.c sbit WAKEUP = 0xD8 ^ 4; // declare the SFR bit address for Wakeup (EICON.4) static void wakeup (void) interrupt 6 // vector addr 33h=51=(6*8)+3 { WAKEUP = 0; // just clear the interrupt request bit
ST ART ST OP
Oscillator
PLL 48 MHz div by 2 CLK24 PCON.0 "RESUME" INT 8051 Signal Resume (USBCS.0)
Restart Delay
8051 receives „suspend‟ interrupt
No USB activity for 3 msec.

Usage tells what a control is actually measuring

Also what should be done with the data

Example: x, y, z input

Report describes the data format

Example: three 8-bit fields
Signal Resume (USBCS.0)
Oscillator restarts, and 8051 receives interrupt 6, from one of two sources: USB bus activity or WAKEUP pin going LOW.
No USB activity for 3 msec.
static void Suspend_ISR (void) interrupt 03
{
EZUSB_IRQ_CLEAR(); USBIRQ = bmSUSP; display_hex(0x7F); PCON |= 1; } // Always clear INT2 flag first // ...then clear SUSPEND IRQ by writing "1" to IRQ bit // decimal point only // set bit zero only: zzzzzzzzzzzzzzzzz