CHENNAI, Jan 8 (Reuters) - India's Tamil Nadu state said on Monday it had signed pacts totalling 6.64 trillion Indian rupees ($80 billion) in investments, ranging from Microsoft and suppliers to Apple to auto giants such as Hyundai Motor.

Global manufacturers are counting on India as a major growth driver as they look to diversify some production from China, while India's growing middle class is also helping local demand.

The commitments announced at an investment summit in the southern state come days before another event in Indian Prime Minister Narendra Modi's home state of Gujarat, which hundreds of domestic and foreign investors are expected to attend.

Among high-profile companies that have committed to invest in Tamil Nadu, known for its automobile and electronic manufacturing clusters, are Hyundai Motor, Royal Enfield and Vietnamese electric vehicle maker VinFast.

Tamil Nadu's government made several announcements on Monday, including on potential energy sector investments of 708 billion rupees from Tata Power Renewable Energy and 362.38 billion rupees from Singapore's Sembcorp.

Adani group entities signed investment pacts worth 427.68 billion rupees, including in green energy, cement and gas, while Microsoft committed to invest 27.4 billion for a data centre.

Separately, Apple supplier Salcomp signed a pact worth 22.71 billion to boost electronic components manufacturing in the state. The announcement followed investment plans made public by other Apple suppliers Pegatron and Tata on Sunday.

"From MoU signing to building the factory, commencing production and even after that ... the government will quickly provide all the required clearances through a single-window system," Tamil Nadu Chief Minister M. K. Stalin said.

The investments are expected to generate direct employment for 1.45 million people, his government said in a statement. ($1 = 83.1075 Indian rupees) (Writing by Haripriya Suresh and Praveen Paramasivam; Editing by Mrigank Dhaniwala and Alexander Smith)