Overview of FM tuner chips

Introduction

This page gives an overview of the various FM chips in current Rockbox targets and experimental Rockbox ports.

Philips/NXP TEA5700 family

This family of FM tuners is the most popular in rockbox targets.

TEA5760/TEA5761

Supported in rockbox by the tea5760uk.c driver.

These chips are used in:

• TEA5760: Meizu M6SL and M3
• TEA5761UK: CreativeZEN, Creative ZVM (30 and 60 GB models), iRiver H10 jr,

TEA5767

Supported in rockbox by the tea5767.c driver.

These chips are used in:

• TEA5767: Coby, CreativeZenV, iAudio U3, MPIO HD200, MPIO HD300, iRiver E100, iRiver H10, iRiver H1xx, iRiver H3xx, iRiver IFP-7xx, OndaVX747, OndaVX767, Philips GoGear 3100 series, Samsung K5, SamsungYH920, Sansa C100, Sansa M200, Sansa M200v4, Zen Micro
• TEA5767HN: Archos Av300, GoGearHDD6330 (HDD1630 and HDD6330)

Sanyo LV24000 family

General features:

• bus interface is a proprietary 3-wire protocol
• tuning requires a multi-step algorithm with assistance of the host microcontroller

These chips are used in:

• LV24000: Meizu M6 T1/TP, Meizu M6 SP
• LV24020: Cowon iAudio7, Sansa e200, Sansa C200
• LV24020LP: Cowon D2

Silicon Laboratories Si4700 family

General features:

• few external components (basically an antenna and a crystal).
• bus interface is either a 2-wire I2C-like protocol, or a 3-wire proprietary protocol
• built-in firmware provides a high-level command interface (e.g. it can automatically seek forwards/backwards)

Some models of this chip provide RDS support (Si4701 and Si4703).

Si4700/Si4702

These chips are basic FM tuners, without RDS support. The Si4700 and Si4702 are supported by the rockbox si4700.c driver.

These chips are used in:

• Si4700: IriverS10, iRiver E10
• Si4702: SansaC200v2, SansaClip, SansaClipv2, SansaClip+, SansaE200v2, SansaFuze, SansaFuzev2, SansaView

Si4701/Si4703

These chips provide the same functionality as the Si4700/Si4702 but with RDS support added. RDS is not yet supported by rockbox.

These chips are used in:

• Si4701: Gigabeat S
• Si4703: SamsungYPS3

Mystery Silabs chip in some Sansa Clip+

Reg

Name

D15

D14

D13

D12

D11

D10

D9

D8

D7

D6

D5

D4

D3

D2

D1

D0

00

01

02

POWERCFG

DMUTE

MONO

ENABLE

03

CHANNEL

CHAN

TUNE

BAND

SPACE

04

DE

MUTE?

SMUTE

05

VOLUME

06

07

08

09

0A

READCHAN

STC

READCHAN

0B

STATUS

RSSI

AFCRL

0C

ID

ID1 = 0x58

0D

ID2 = 0x00 or not

0E

0F

Radio chip detection

Read 128 bytes from the chip, check if bytes[4] == 0x58. If this is the case, the chip has been detected. Now write 2 bytes (0x200) and wait a bit (10 ms), then check bytes[6] and compare against 0. If 0, write a set of 72 initialisation values, else write a set of 82 initialisation values.

Mute radio

Set or clear the DMUTE bit, just like the si4700. Also set bits 9 and 10 of register 0x04 and the four lowest bits of register 5 (VOLUME).

Force mono

Set or clear the MONO bit, just like the si4700.

Set band

Write the 2-bit band code in BAND, similar to the si4700, but in a different location.

The lowest bit of BAND indicates the start of the band as follows: 0 = 76 MHz, 1 = 87 MHz

Power down

Write either 0 (powerdown) or 1 (powerup) to register 0x02. Set register bits 9 and 10 of register 0x04.

Set soft-mute

On un-mute, clear bit 9 of register 0x04. On mute, set bits 9 and 10 of register 0x04.

Set de-emphasis

Set or clear bit 11 of register 0x04, just like the si4700.

Set channel spacing

Write the 2-bit channel space code in SPACE, similar to si4700, but in a different location.

Set frequency

Calculate the channel code CHAN = (Fdesired - Flow) / 50 KHz, where Fdesired is the frequency to tune to and Flow is the lowest frequency in this band. Then write CHAN together with the TUNE bit set. Wait 70 ms, read 4 bytes status. Verify that READCHAN = CHAN and that STC is set, if so we're done, otherwise clear TUNE and try the whole procedure again up to 25 times.

Read RSSI

Read 4 bytes from the radio chip. If AFCRL is set, assume 0, otherwise return RSSI bits.

Samsung S1A0903X01

Supported in rockbox by the s1a0903x01.c driver

Used in:

• Archos FM recorder

Niigata family

There is no driver yet for this family of FM tuners in rockbox.

General features:

• bus interface is a 2-wire I2C protocol, or a 3-wire protocol
• Product information page

These chips are used in:

• NS953M: SamsungYPT7