How I can turn-on word alignment in Keil C51? I have such definition of USB-descriptors for Cypress EZ-USB chip CY7C68013:
const DEVICEDSCR code TestSyncSlave_DeviceDescriptor = { // Device descriptor sizeof(DEVICEDSCR), // 0x00 Length of this descriptor DEVICE_DSCR, // 0x01 Descriptor type USBSPEC, // 0x02 USB Specification Release Number VENDOR_SPECIFIC, // 0x04 Class Code 0x00, // 0x05 Sub Class Code 0x00, // 0x06 Protocol EP0_MAX_PACKET_SIZE, // 0x07 Maximum Endpoint 0 Packet Size VID_EPOS, // 0x08 Vendor ID PID_ANALYSER, // 0x0a Product ID DID_ANALYSER, // 0x0c DeviceBCD Device Release Number STRING_INDEX_MANUFACTURER, // 0x0e Index of string descriptor describing manufacturer STRING_INDEX_PRODUCT, // 0x0f Index of string descriptor describing product 0x00, // 0x10 Index of string descriptor describing serial number 0x01 // 0x11 Number of configurations }; /////////////////////////////////////////////////////////////////////////////// const DEVICEQUALDSCR code TestSyncSlave_DeviceQualifierDescriptor = { // Device Qualifier descriptor sizeof(DEVICEQUALDSCR), // 0x00 Length of this descriptor DEVQUAL_DSCR, // 0x01 Descriptor type USBSPEC, // 0x02 USB Specification Release Number VENDOR_SPECIFIC, // 0x04 Class Code 0x00, // 0x05 Sub Class Code 0x00, // 0x06 Protocol EP0_MAX_PACKET_SIZE, // 0x07 Maximum Endpoint 0 Packet Size 0x01, // 0x08 Number of configurations 0x00 // 0x09 Reserve }; /////////////////////////////////////////////////////////////////////////////// const DEVICECONFG code TestSyncSlave_HS_Config = { // Configuration when connected to a High Speed host { // Configuration Descriptor sizeof(CONFIGDSCR), // 0x00 bLength: Length of this descriptor CONFIG_DSCR, // 0x01 Type (CONFIGURATION_DESC or CONFIGURATION_DESC) LSB(sizeof(DEVICECONFG)), // 0x02 wTotalLength: Total length for this configuration MSB(sizeof(DEVICECONFG)), // 0x02 wTotalLength: Total length for this configuration NUM_INTERFACES, // 0x04 bNumInterfaces: Number of Interfaces 0x01, // 0x05 bConfigurationValue: Number of this configuration 0x00, // 0x06 iConfiguration: Index of string descriptor describing this configuration CONFIG_ATTRIBUTES, // 0x07 bmAttributes: 7:AlwaysSet|6:SelfPowered|5:RemoteWakeup 150 // 0x08 bMaxPower: Max USB power (in 2mA units) }, { // Interface Descriptor: sizeof(INTRFCDSCR), // 0x00 Size of this descriptor INTRFC_DSCR, // 0x01 Type 0x00, // 0x02 Number of this interface 0x00, // 0x03 Alternate interface ENDPOINT_COUNT, // 0x04 Number of endpoints in this interface (without EP0) VENDOR_SPECIFIC, // 0x05 Class Code 0x00, // 0x06 Sub Class Code 0x00, // 0x07 Device Protocol 0x00, // 0x08 Index of string descriptor describing this interface }, { // Endpoint Descriptors: Type Dir MaxPkt UsbEp Poll {MAKE_ENDPOINT_DESCRIPTOR( EP_BULK, EP_IN, 512, 0x86, 0 )}, {MAKE_ENDPOINT_DESCRIPTOR( EP_BULK, EP_OUT, 64, 0x01, 0 )}, {MAKE_ENDPOINT_DESCRIPTOR( EP_BULK, EP_IN, 64, 0x81, 0 )} } }; //In such definition last structure is missalignment, so I must align it... /////////////////////////////////////////////////////////////////////////////// const DEVICECONFG code TestSyncSlave_FS_Config = { // Configuration when connected to a Full Speed host { // Configuration descriptor sizeof(CONFIGDSCR), // 0x00 Length of this descriptor CONFIG_DSCR, // 0x01 Type (CONFIGURATION_DESC or OTHER_SPEED_CONFIGURATION_DESC) LSB(sizeof(DEVICECONFG)), // 0x02 wTotalLength: Total length for this configuration MSB(sizeof(DEVICECONFG)), // 0x02 wTotalLength: Total length for this configuration NUM_INTERFACES, // 0x04 Number of Interfaces 0x01, // 0x05 Number of this configuration 0x00, // 0x06 Index of string descriptor describing this configuration CONFIG_ATTRIBUTES, // 0x07 bmAttributes: 7:AlwaysSet|6:SelfPowered|5:RemoteWakeup 150 // 0x08 Max USB power (in 2mA units) }, { // Interface Descriptor: sizeof(INTRFCDSCR), // 0x00 Size of this descriptor INTRFC_DSCR, // 0x01 Type 0x00, // 0x02 Number of this interface 0x00, // 0x03 Alternate interface ENDPOINT_COUNT, // 0x04 Number of endpoints in this interface (without EP0) VENDOR_SPECIFIC, // 0x05 Class Code 0x00, // 0x06 Sub Class Code 0x00, // 0x07 Device Protocol 0x00, // 0x08 Index of string descriptor describing this interface }, { // Endpoint Descriptors: Type Dir MaxPkt UsbEp Poll {MAKE_ENDPOINT_DESCRIPTOR( EP_BULK, EP_IN, 64, 0x86, 0 )}, {MAKE_ENDPOINT_DESCRIPTOR( EP_BULK, EP_OUT, 64, 0x01, 0 )}, {MAKE_ENDPOINT_DESCRIPTOR( EP_BULK, EP_IN, 64, 0x81, 0 )} } };
EZ-USB needs that each USB-descriptor was word alignment. How can I do this in Keil C51(any directive such as #pragma pack)?
I think doing it in the 'C' source code with some suitable preprocessor checking would be safer...?
Maybe this could help: http://www.keil.com/support/man/docs/c51/c51_offsetof.htm
Yes this more safer, than manualy setup code segments. Especially as after every change of code segment need check, that no overlap.
In cypress examples, i find interest way to align on word, but only in asm:
;;----------------------------------------------------------------------------- ;; Global Variables ;;----------------------------------------------------------------------------- ; rseg DSCR ;; locate the descriptor table in on-part memory. CSEG AT 100H DeviceDscr: db DSCR_DEVICE_LEN ;; Descriptor length db DSCR_DEVICE ;; Decriptor type dw 0002H ;; Specification Version (BCD) db 00H ;; Device class db 00H ;; Device sub-class db 00H ;; Device sub-sub-class db 64 ;; Maximum packet size dw 0B404H ;; Vendor ID dw 0310H ;; Product ID (Sample Device) dw 0000H ;; Product version ID db 1 ;; Manufacturer string index db 2 ;; Product string index db 0 ;; Serial number string index db 1 ;; Number of configurations org (($ / 2) +1) * 2 DeviceQualDscr: db DSCR_DEVQUAL_LEN ;; Descriptor length db DSCR_DEVQUAL ;; Decriptor type dw 0002H ;; Specification Version (BCD) db 00H ;; Device class db 00H ;; Device sub-class db 00H ;; Device sub-sub-class db 64 ;; Maximum packet size db 1 ;; Number of configurations db 0 ;; Reserved
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One more time, In an 8-bit processor, the word size is 8 bits.
You need to stop using "word" as if it has some definite, universal size - it does not!
If you mean "16-bit alignment" or "even-address" alignment, you need to say that explicitly - otherwise you are going to cause confusion and, probably, end up in trouble.
Have you looked into using sizeof and/or offsetof to do it in 'C'...?
I not see the way, how offsetof construction can help me...
In a similar vein to your assembler, how about something like:
#if (offsetof(x)/2)*2 != offsetof(x) // Offset is odd - packing needed #endif
Than how put to even-aligned address first descriptor in chain? :)