Tiny Tapeout - Smartcard PLL Clock Generator

• Top module: tt_um_william_pll
• Language: Verilog
• Target shuttle: SKY26a (sky130A, digital tile)
• Project docs: docs/info.md

Creator

• William Anthony
• Electrical Engineering, Bandung Institute of Technology (ITB)
• Built in 6th semester (admitted in 2023)
• LinkedIn: https://www.linkedin.com/in/wlmoi/
• GitHub: https://github.com/wlmoi
• Instagram: https://www.instagram.com/wlmoi/

What is Tiny Tapeout?

Tiny Tapeout is an educational project that aims to make it easier and cheaper than ever to get your digital and analog designs manufactured on a real chip.

To learn more and get started, visit https://tinytapeout.com.

Overview

This design wraps a smartcard-oriented PLL model into the Tiny Tapeout user module interface. The reference input uses Tiny Tapeout clk, and the PLL is intentionally controlled by an explicit enable bit.

How activation works

• ena must be high (project selected)
• rst_n must be high (reset released)
• ui[0] must be set to 1 to enable PLL operation

When ui[0] is set back to 0, the PLL path is intentionally disabled and output clocks are expected to stop.

Pin map summary

• Inputs (ui_in)
  • ui[0]: PLL enable
  • ui[7:4]: divider ratio config nibble
• Bidirectional (uio)
  • uio[3:0] input: charge pump gain config
  • uio[7:4] output: VCO monitor bits
• Outputs (uo_out)
  • uo[0]: lock
  • uo[1]: almost_lock
  • uo[2]: clk_div4
  • uo[3]: clk_div2
  • uo[4]: pll_clk_out
  • uo[5]: pfd_up
  • uo[6]: pfd_down
  • uo[7]: enable status

Local test

From test/ run:

make -B

The cocotb test verifies disabled state, enabled oscillation, and disabled-again behavior.

Resources

• FAQ
• Digital design lessons
• Learn how semiconductors work
• Join the community
• Build your design locally

Credits

Project template and submission flow are based on the Tiny Tapeout project ecosystem and documentation.

Submit your design

• Submit your design to the next shuttle.

Share your project

• LinkedIn #tinytapeout @TinyTapeout
• Mastodon #tinytapeout @matthewvenn
• X (formerly Twitter) #tinytapeout @tinytapeout
• Bluesky @tinytapeout.com