Difference between revisions of "PACmate20 Braille Display"
From Hackstrich
(Added detailed information on USB descriptor info.) |
(IN endpoint is 02 not 82) |
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| − | + | The Freedom Scientific [http://www.freedomscientific.com/fs_products/PACmate_20.asp PACmate 20] is a 20-cell braille display with two pushbuttons over each cell, and two 'whiz wheels' (mousewheel-type wheels) on either side of the braille area. It connects to a PC or other device via USB, and can be attached to the [http://www.freedomscientific.com/fs_products/PACmate2.asp PACmate notetaker] to integrate them into one device. | |
| − | The [http://www.freedomscientific.com/fs_products/PACmate_20.asp PACmate 20] is a 20-cell braille display with two pushbuttons over each cell, and two 'whiz wheels' (mousewheel-type wheels) on either side of the braille area. It connects to a PC or other device via USB, and can be attached to the [http://www.freedomscientific.com/fs_products/PACmate2.asp PACmate notetaker] to integrate them into one device. | ||
| − | + | == Notable Chips == | |
{| border="1" | {| border="1" | ||
!Chip | !Chip | ||
| Line 21: | Line 20: | ||
|} | |} | ||
| − | + | == USB Descriptors == | |
<pre> | <pre> | ||
Configuration descriptor: | Configuration descriptor: | ||
| Line 47: | Line 46: | ||
Endpoint descriptor: | Endpoint descriptor: | ||
| − | Endpoint address: | + | Endpoint address: 02 [10000010: IN endpoint 1] |
Attributes: 02 [01000000: Bulk] | Attributes: 02 [01000000: Bulk] | ||
Maximum packet size: 0040 [64 bytes] | Maximum packet size: 0040 [64 bytes] | ||
| Line 53: | Line 52: | ||
</pre> | </pre> | ||
| − | === Images | + | == Protocol == |
| + | Protocol documentation all taken using BRLTTY's FreedomScientific driver as a reference implementation. Packets sent to the PACmate20 display all follow a standard format, detailed below. | ||
| + | === Packet Format === | ||
| + | <pre> | ||
| + | byte type | ||
| + | byte arg1 | ||
| + | byte arg2 | ||
| + | byte arg3 | ||
| + | byte payload[256] | ||
| + | OR | ||
| + | byte manufacturer[24] | ||
| + | byte model[16] | ||
| + | byte firmware_version[8] | ||
| + | OR | ||
| + | byte extended_keys[4] | ||
| + | </pre> | ||
| + | |||
| + | === C Structure === | ||
| + | <pre> | ||
| + | typedef struct { | ||
| + | unsigned char type; | ||
| + | unsigned char arg1; | ||
| + | unsigned char arg2; | ||
| + | unsigned char arg3; | ||
| + | } PacketHeader; | ||
| + | |||
| + | typedef struct { | ||
| + | PacketHeader header; | ||
| + | union { | ||
| + | unsigned char bytes[0X100]; | ||
| + | struct { | ||
| + | char manufacturer[24]; | ||
| + | char model[16]; | ||
| + | char firmware[8]; | ||
| + | } info; | ||
| + | struct { | ||
| + | unsigned char bytes[4]; | ||
| + | } extkey; | ||
| + | } payload; | ||
| + | } Packet; | ||
| + | </pre> | ||
| + | |||
| + | == Images == | ||
[[Image:PACmate20_Internal.png]] | [[Image:PACmate20_Internal.png]] | ||
[[Category:Products]] | [[Category:Products]] | ||
Latest revision as of 19:01, 9 October 2011
The Freedom Scientific PACmate 20 is a 20-cell braille display with two pushbuttons over each cell, and two 'whiz wheels' (mousewheel-type wheels) on either side of the braille area. It connects to a PC or other device via USB, and can be attached to the PACmate notetaker to integrate them into one device.
Notable Chips
| Chip | Chip Function | Use in Product |
|---|---|---|
| C8051F320 | Microcontroller w/ USB | Brains of the display, talks to the PC/device natively over USB. |
| LM358 | Op-amp | Don't know |
| TLC555 | Timer | Near large cap, small caps, and inductors. May be part of the HV charge pump? |
USB Descriptors
Configuration descriptor: Total length: 0020 Number of Interfaces: 01 Configuration value: 01 Configuration string: 00 Attributes: 80 [Device doesn't have own power, can't generate remote wakeups] Maximum power usage FA [500mA] Interface descriptor: Interface number: 00 Alternate: 00 Endpoints: 02 Class: FF [Vendor Specific] Subclass: 00 [Ignored: Class FF] Protocol: 00 [Ignored: Class FF] Interface string: 00 Endpoint descriptor: Endpoint address: 01 [10000000: OUT endpoint 1] Attributes: 02 [01000000: Bulk] Maximum packet size: 0040 [64 bytes] Polling interval: 00 [Ignored: Not isochronous or interrupt type] Endpoint descriptor: Endpoint address: 02 [10000010: IN endpoint 1] Attributes: 02 [01000000: Bulk] Maximum packet size: 0040 [64 bytes] Polling interval: 00 [Ignored: Not isochronous or interrupt type]
Protocol
Protocol documentation all taken using BRLTTY's FreedomScientific driver as a reference implementation. Packets sent to the PACmate20 display all follow a standard format, detailed below.
Packet Format
byte type byte arg1 byte arg2 byte arg3 byte payload[256] OR byte manufacturer[24] byte model[16] byte firmware_version[8] OR byte extended_keys[4]
C Structure
typedef struct {
unsigned char type;
unsigned char arg1;
unsigned char arg2;
unsigned char arg3;
} PacketHeader;
typedef struct {
PacketHeader header;
union {
unsigned char bytes[0X100];
struct {
char manufacturer[24];
char model[16];
char firmware[8];
} info;
struct {
unsigned char bytes[4];
} extkey;
} payload;
} Packet;
Images
