Section 4. USB Communications
SERIAL_NUM PROPERTY
Property ID: | 1 |
Property Type: | String |
Length: | 0 – 15 bytes |
Get Property: | Yes |
Set Property: | Yes |
Default Value: | The default value is no string with a length of zero. |
Description: | The value is an ASCII string that represents the device’s serial number. This |
| string can be 0 – 15 bytes long. This property is stored in |
| EEPROM memory so it will not change when the unit is power cycled. The |
| value of this property, if any, will be sent to the host when the host requests |
| the USB string descriptor. When this property is changed, the unit must be |
| power cycled to have these changes take effect for the USB descriptor. If a |
| value other than the default value is desired, it can be set by the factory upon |
| request. Examples follow. |
Example Set SERIAL_NUM property Request (Hex):
Cmd Num | Data Len | Prp ID | Prp Value |
01 | 04 | 01 | 31 32 33 |
Example Set SERIAL_NUM property Response (Hex):
Result Code | Data Len | Data |
00 | 00 |
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Example Get SERIAL_NUM property Request (Hex):
Cmd Num | Data Len | Prp ID |
00 | 01 | 01 |
Example Get SERIAL_NUM property Response (Hex):
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| Result Code | Data Len | Prp Value |
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| 00 | 03 | 31 32 33 |
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POLLING_INTERVAL PROPERTY |
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Property ID: | 2 |
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Property Type: | Byte |
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Length: | 1 byte |
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Get Property: | Yes |
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Set Property: | Yes |
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Default Value: | 10 |
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Description: | The value is a byte that represents the devices polling interval for the Interrupt | ||||
| In Endpoint. The value can be set in the range of 1 – 255 and has units of | ||||
| milliseconds. The polling interval tells the host how often to poll the device | ||||
| for card data packets. For example, if the polling interval is set to 10, the host | ||||
| will poll the device for card data packets every 10ms. This property can be | ||||
| used to speed up or slow down the time it takes to send card data to the host. | ||||
| The | ||||
| bus bandwidth used by the device, and slowing down the card data transfer |
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