MichaelBell/tt-audio-pmod6Tiny Tapeout Audio Pmod
Tt audio pmod is an open-source printed circuit board by MichaelBell, from the MichaelBell/tt-audio-pmod repository on GitHub, published under the Apache-2.0 licence. It is a 2-layer board of 45.7 × 20.3 mm with 18 parts on 19 nets, routed with 93 tracks and 16 vias.
It is built around the 74LVCE1G126SE-7-85, 10129382-912001BLF and 3362P-1-201LF, with the MLF2012-3R3K, PJ-320B and ZL-YDW1407-4005P-7.6 among its other parts. Its parts include 6 capacitors, 4 resistors, 4 connectors, 1 IC and 1 inductor. It belongs with the audio and music boards of this library.
This Pmod is designed to play mono PWM audio from out[7] or bidir[7], while allowing a second Pmod to be plugged in, passing through bidir[0-6] or out[0-6].
The design has a low pass filter, to allow a large range of audio to be played the cutoff frequency is quite high. It is therefore recommended that the PWM frequency is at least 200kHz to get good results.
If the piezo is selected with the jumper, it is driven after the low pass filter with no further filtering.
If the headphone jack is selected, AC coupling is applied to give a balanced signal.
The volume trim pot should be turned down to around 30-35 ohms to give nominal line level when the output is connected to a high impedance line in. If using headphones with a low impedance it should be turned up towards the high end of the range (180-200 ohms).
IO 7 on the second Pmod is pulled high, which allows compatibility with the QSPI Pmod.
The Pmod was designed in KiCad 8, here is the schematic.
This example project generates a PWM output sampling a sine wave of a configurable frequency.
The frequency response of the design was simulated in ltspice:
The ltspice simulations are in the sim directory.
The first version of the Pmod is being manufactured and will be tested soon.
Designed for Tiny Tapeout by RebelMike with the help of the excellent Tiny Tapeout Discord community.
Copyright 2024 Mike Bell
Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.
Image on the reverse is by ArtRose on Pixabay. Used under the Pixabay Content License
| Qty | Value | Footprint | References |
|---|---|---|---|
| 3 | 100nF | Capacitor_SMD:C_0603_1608Metric | C1, C4, C6 |
| 1 | 10129382-912001BLF | kicad-tinytapeout-pmod-lib:PinHeader_2x06_P2.54mm_PMODPeriph2B | J1 |
| 1 | 10uF | Capacitor_SMD:C_0805_2012Metric | C3 |
| 1 | 120R | Resistor_SMD:R_0603_1608Metric | R1 |
| 1 | 1k | Resistor_SMD:R_0603_1608Metric | R4 |
| 1 | 3362P-1-201LF | LCSC:TRIM_3362P-1-102 | RV1 |
| 1 | 33R | Resistor_SMD:R_0603_1608Metric | R2 |
| 1 | 470R | Resistor_SMD:R_0603_1608Metric | R3 |
| 1 | 47nF | Capacitor_SMD:C_0603_1608Metric | C5 |
| 1 | 47uF | Capacitor_SMD:C_0805_2012Metric | C2 |
| 1 | 74LVCE1G126SE-7 | Package_TO_SOT_SMD:SOT-353_SC-70-5 | U1 |
| 1 | Female header | Header:PinSocket_2x06_P2.54mm_Vertical_Column | J2 |
| 1 | MLF2012-3R3K | Inductor_SMD:L_0805_2012Metric | L1 |
| 1 | Male header | Connector_PinHeader_2.54mm:PinHeader_1x03_P2.54mm_Vertical | J4 |
| 1 | PJ-320B | LCSC:BOOMELE_PJ-320B | J5 |
| 1 | ZL-YDW1407-4005P-7.6 | LCSC:BUZ-TH_BD14.0-P7.60-D0.7-FD | PIEZO1 |
It measures 45.7 × 20.3 mm and has 2 copper layers, 1.6 mm thick.
18 parts, built around the 74LVCE1G126SE-7-85, 10129382-912001BLF, 3362P-1-201LF and MLF2012-3R3K. The full list of its parts is on this page, with links to each part's symbol and footprint where PCBKit's library has them.
From the MichaelBell/tt-audio-pmod repository on GitHub, at the commit this page was made from: the board is tt-audio-pmod.kicad_pcb and its schematic tt-audio-pmod.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Its repository publishes it under the Apache-2.0 licence: you may reuse it on that licence's terms (keep the author's notice, and for a copyleft licence share your changes alike).
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