Difference between revisions of "J-Link OB"
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=J-Link OB SAM3U NordicSemi= |
=J-Link OB SAM3U NordicSemi= |
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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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+ | |||
=J-Link-OB SAM3U= |
=J-Link-OB SAM3U= |
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=J-Link-OB-RX621-ARM-SWD= |
=J-Link-OB-RX621-ARM-SWD= |
Revision as of 09:17, 26 March 2019
Contents
J-Link OB SAM3U NordicSemi
VCOM functionality
This J-Link model supports VCOM.
Supported baudrates
This J-Link OB supports max. 1 MBaud. The internal divider is calculated as follows:
Baudrate = 96000000 / Div * 16; Div = 96000000 / (Baudrate * 16);
Note: The real baudrate and the selected one should not deviate more than 3% to guarantee proper communication on VCOM.
Pin driving policy
The following pins are available on this OB:
- OB_Tx (driven by J-Link OB)
- OB_Rx (driven by target)
- CTS (driven by target. LOW == Target ready to receive data)
- RTS (driven by J-Link OB. LOW == J-Link OB ready to receive data)
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.
J-Link OB stops driving the RTS pin if J-Link OB detects that hardware flow control is not used on the target side.
Hardware flow control support
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. This is done as follows:
- 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)
Force or disable hardware flow control
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:
SetHWFC Enable/Disable/Force
Note: This setting gets active immediately and survives a power-cycle of J-Link.
- Enable: Default. Enables hardware flow control and runtime auto-detection
- Disable: Disables hardware flow control (never used)
- Force: Enables hardware flow control and bypasses runtime auto-detection (RTS is kept driven and CTS is kept sampling)
Minimum requirements
- J-Link software V6.33h (beta) or later (Download latest beta)
- J-Link software V6.34 (release) or later (Download latest release)
- J-Link OB SAM3U NordicSemi running firmware from V6.33h or later