Difference between revisions of "J-Link OB SAM3U NordicSemi"
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| + | #REDIRECT [[J-Link OB]] |
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| − | __TOC__ |
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| − | = VCOM functionality = |
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| − | This J-Link model supports VCOM. |
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| − | == Supported baudrates == |
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| − | This J-Link OB supports max. 1 MBaud. The internal divider is calculated as follows: |
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| − | Baudrate = 96000000 / Div * 16; |
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| − | Div = 96000000 / (Baudrate * 16); |
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| − | '''Note:''' The real baudrate and the selected one should not deviate more than 3% to guarantee proper communication on VCOM. |
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| − | |||
| − | == Pin driving policy == |
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| − | The following pins are available on this OB: |
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| − | * OB_Tx (driven by J-Link OB) |
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| − | * OB_Rx (driven by target) |
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| − | * CTS (driven by target. LOW == Target ready to receive data) |
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| − | * RTS (driven by J-Link OB. LOW == J-Link OB ready to receive data) |
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| − | J-Link OB starts driving its VCOM output pins as soon as it receives a "set baudrate" command. This command is send by the PC as soon as a COM port is opened. Unfortunately, there is no specific command / packet etc. send by the PC in case a COM port is opened. Therefore the "set baudrate" approach is the only one to detect COM port activity. |
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| − | J-Link OB stops driving the RTS pin if J-Link OB detects that hardware flow control is not used on the target side. |
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| − | == Hardware flow control support == |
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| − | Hardware flow control is supported by this J-Link OB. By default, J-Link detects at runtime if the target uses flow control or not. |
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| − | This is done as follows: |
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| − | * If CTS is detected as HIGH (Target not ready) before the first character is sent by J-Link OB, the pin is assumed to be not used by the target and flow control on the J-Link side gets disabled (CTS is ignored from now on, J-Link stops driving RTS) |
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| − | === Force or disable hardware flow control === |
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| − | It is possible to configure J-Link OB to bypass the hardware flow control auto-detection in the firmware and assume that hardware flow control is always or never used. This can be done via J-Link Commander and the following command: |
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| − | SetHWFC Enable/Disable/Force |
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| − | '''Note:''' This setting gets active immediately and survives a power-cycle of J-Link. |
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| − | * '''Enable:''' Default. Enables hardware flow control and runtime auto-detection |
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| − | * '''Disable:''' Disables hardware flow control (never used) |
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| − | * '''Force:''' Enables hardware flow control and bypasses runtime auto-detection (RTS is kept driven and CTS is kept sampling) |
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| − | [[File:OB_SAM3U_NordicSemi_SetHWFC.png|Force hardware flow control|thumb|none]] |
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| − | ==== Minimum requirements ==== |
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| − | * J-Link software V6.33h (beta) or later ([https://www.segger.com/downloads/jlink/#J-LinkSoftwareAndDocumentationPackBeta Download latest beta]) |
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| − | * J-Link software V6.34 (release) or later ([https://www.segger.com/downloads/jlink/#J-LinkSoftwareAndDocumentationPack Download latest release]) |
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| − | * J-Link OB SAM3U NordicSemi running firmware from V6.33h or later |
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Latest revision as of 10:23, 26 March 2019
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