> For the complete documentation index, see [llms.txt](https://sandbox-docs.verifone.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://sandbox-docs.verifone.com/s-adk-5.1-programmers-guide/readme/modules/group___l_e_d___s_t_a_t_e_s.md).

# LED states

[Macros](#define-members)

These are the states of the three MSR LEDs which can be set by [MSR\_SwitchLeds()](/s-adk-5.1-programmers-guide/readme/files/dir_b259c67979486db4cd1816234700c14a/dir_699851f087f6e6136e28f04fc8a16e7d/msr_8h.md#abca7e8953c8430d80f51c867c7699fa6). On devices that don't have multicolored LEDs, all "color defines" are equivalent and imply "LED on". As there is currently no device with multicolored LEDs, multicolor feature is not implemented yet. [More...](#details)

|         |                                                                  |
| ------- | ---------------------------------------------------------------- |
| Macros  |                                                                  |
| #define | [MSR\_LED\_OFF](#ga732d5b4b7e9dc86936491616790f521c)   0x0000    |
| #define | [MSR\_LED\_WHITE](#gaf154b2af61487136381570a0a65eae95)   0x0001  |
| #define | [MSR\_LED\_RED](#ga9d645bdc79cf473ad1a4cb2c16e0d540)   0x0002    |
| #define | [MSR\_LED\_GREEN](#ga2e04bf1f17254549f2b8d591a4ea9474)   0x0003  |
| #define | [MSR\_LED\_BLUE](#ga02373c78ce2427317ac035d08e1fdc17)   0x0004   |
| #define | [MSR\_LED\_YELLOW](#ga5ed7fb7eb095670a3901df7f3ddebc50)   0x0005 |
| #define | [MSR\_LED\_BLINK](#gac0602288caa7d6664024a579091ccaa2)   0x0100  |

### DetailedDescription <a href="#detailed-description" id="detailed-description"></a>

These are the states of the three MSR LEDs which can be set by [MSR\_SwitchLeds()](/s-adk-5.1-programmers-guide/readme/files/dir_b259c67979486db4cd1816234700c14a/dir_699851f087f6e6136e28f04fc8a16e7d/msr_8h.md#abca7e8953c8430d80f51c867c7699fa6). On devices that don't have multicolored LEDs, all "color defines" are equivalent and imply "LED on". As there is currently no device with multicolored LEDs, multicolor feature is not implemented yet.

### MacroDefinition Documentation <a href="#macro-definition-documentation" id="macro-definition-documentation"></a>

### MSR\_LED\_BLINK <a href="#gac0602288caa7d6664024a579091ccaa2" id="gac0602288caa7d6664024a579091ccaa2"></a>

\#define MSR\_LED\_BLINK   0x0100

LED blinks (500ms on, 500ms off), must be combined with one of the "color defines".

### MSR\_LED\_BLUE <a href="#ga02373c78ce2427317ac035d08e1fdc17" id="ga02373c78ce2427317ac035d08e1fdc17"></a>

\#define MSR\_LED\_BLUE   0x0004

LED shines blue.

### MSR\_LED\_GREEN <a href="#ga2e04bf1f17254549f2b8d591a4ea9474" id="ga2e04bf1f17254549f2b8d591a4ea9474"></a>

\#define MSR\_LED\_GREEN   0x0003

LED shines green.

### MSR\_LED\_OFF <a href="#ga732d5b4b7e9dc86936491616790f521c" id="ga732d5b4b7e9dc86936491616790f521c"></a>

\#define MSR\_LED\_OFF   0x0000

LED is switched off.

### MSR\_LED\_RED <a href="#ga9d645bdc79cf473ad1a4cb2c16e0d540" id="ga9d645bdc79cf473ad1a4cb2c16e0d540"></a>

\#define MSR\_LED\_RED   0x0002

LED shines red.

### MSR\_LED\_WHITE <a href="#gaf154b2af61487136381570a0a65eae95" id="gaf154b2af61487136381570a0a65eae95"></a>

\#define MSR\_LED\_WHITE   0x0001

LED shines white.

### MSR\_LED\_YELLOW <a href="#ga5ed7fb7eb095670a3901df7f3ddebc50" id="ga5ed7fb7eb095670a3901df7f3ddebc50"></a>

\#define MSR\_LED\_YELLOW   0x0005

LED shines yellow.


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter:

```
GET https://sandbox-docs.verifone.com/s-adk-5.1-programmers-guide/readme/modules/group___l_e_d___s_t_a_t_e_s.md?ask=<question>&goal=<endgoal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal.

The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.