---
layout: page
title: "LED documentation"
permalink: /hardware/sh7305/calmezvous.html
author: Yatis
---

## Fx9860 - LED documentations

Check if the LED exist
To check if the LED exist we have just to check the 4th bit of Port Q;
If the bit is down the LED exist.

```c
int fx9860_check_led()
{
	volatile uint8_t *portQ

	portQ = (void*)0xa405013a;
	if (*portQ & 4)
	{
		printk("fx9860 with no LED !\n");
		return(1);
	}
	printk("fx9860 with LED !\n");
	return (0);
}
```

---

## Turn ON the LED
To turn ON the LED you need first to select the LED "module" using Port Selector A (`0xa405014e`).
After that, Stop the external clock used to supplie the LED using the first bit of `0xa44c0020` (DDCL_CNCR Extern Clock Control regsiter).
Then update the extern clock settings and restart the extern clock.
Known clock configuration (used by Casio):
* 0x0000 - LED off.
* 0xc003 - LED low.
* 0xc001 - LED medium.
* 0xc005 - LED high.

```c
int fx9860_test_led()
{
	uint16_t config[] = {0x0000, 0xc003, 0xc001, 0xc005};
	//volatile uint16_t *pacr    = (void*)0xa4050100;
	volatile uint16_t *psela   = (void*)0xa405014e;
	volatile uint8_t *ddk_cncr = (void*)0xa44c0020;
	volatile uint16_t *ddclk0  = (void*)0xa44c0000;

	// Select LED module.
	//*pacr = *pacr & 0x3fc;	// Used by Casio but useless here (LED output config?)
	*psela = *psela & 0xfcff;	// Stop module.
	*psela = *psela | 0x0100;	// Select LED pin to ouput


	// LED loop, change luminosity.
	int offset = 1;
	int index = 0;
	printk("Start LED clock !\n");
	while (1)
	{
		printk("Update LED Clock = %#x\n", config[index]);
		*ddk_cncr = *ddk_cncr & 0xfe;	// Stop External Clock 0.
		*ddclk0 = config[index];	// Use Casio clock config.
		*ddk_cncr = *ddk_cncr | 0x01;	// Start LED clock.

		// Wait a bit (crappy method)
		for (int i = 0 ; i < 5000000 ; i = i + 1);

		// Update Configuration part.
		index = index + offset;
		if (index == 3)
			offset = -1;
		if (index == 0)
			offset = 1;
	}
}

<br>

---

## Technical note:
Casio use the Port A to remove some bits but I don't known exactely why (I suppos is to configure LED pin to output).