mirror of https://github.com/efabless/caravel.git
84 lines
4.3 KiB
ReStructuredText
84 lines
4.3 KiB
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<!---
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# SPDX-FileCopyrightText: 2020 Efabless Corporation
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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#
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# SPDX-License-Identifier: Apache-2.0
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-->
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=========================
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Clamp List
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=========================
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============================ =========================== ====== ====== ====== ====== =====
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Pad Instance Clamp connections
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---------------------------- --------------------------- ---------------------------------
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-- -- DRN1 SRC1 DRN2 SRC2 B2B
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============================ =========================== ====== ====== ====== ====== =====
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sky130_ef_io__vddio_hvc_pad \mgmt_vddio_hvclamp_pad[0] vddio vssio
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sky130_ef_io__vddio_hvc_pad \mgmt_vddio_hvclamp_pad[1] vddio vssio
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sky130_ef_io__vssio_hvc_pad \mgmt_vssio_hvclamp_pad[0] vddio vssio
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sky130_ef_io__vssio_hvc_pad \mgmt_vssio_hvclamp_pad[1] vddio vssio
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sky130_ef_io__vdda_hvc_pad mgmt_vdda_hvclamp_pad vdda vssa
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sky130_ef_io__vssa_hvc_pad mgmt_vssa_hvclamp_pad vdda vssa
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sky130_ef_io__vdda_hvc_pad user1_vdda_hvclamp_pad vdda1 vssa1
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sky130_ef_io__vssa_hvc_pad user1_vssa_hvclamp_pad vdda1 vssa1
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sky130_ef_io__vdda_hvc_pad user2_vdda_hvclamp_pad vdda2 vssa2
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sky130_ef_io__vssa_hvc_pad user2_vssa_hvclamp_pad vdda2 vssa2
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sky130_ef_io__vccd_lvc_pad mgmt_vccd_lvclamp_pad vccd vssio vccd vssd vssa
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sky130_ef_io__vssd_lvc_pad mgmt_vssd_lvclmap_pad vccd vssio vccd vssd vssa
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sky130_ef_io__vccd_lvc_pad user1_vccd_lvclamp_pad vccd1 vssd1 vccd1 vssd vssio
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sky130_ef_io__vssd_lvc_pad user1_vssd_lvclmap_pad vccd1 vssd1 vccd1 vssd vssio
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sky130_ef_io__vccd_lvc_pad user2_vccd_lvclamp_pad vccd2 vssd2 vccd2 vssd vssio
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sky130_ef_io__vssd_lvc_pad user2_vssd_lvclmap_pad vccd2 vssd2 vccd2 vssd vssio
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============================ =========================== ====== ====== ====== ====== =====
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Overlay types used:
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===================
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1. hvc_pad: vddio -> vssio
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2. hvc_pad: vdda -> vssa
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3. lvc_pad: vccd -> vssio, vccd -> vssd vssa
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4. lvc_pad: vccd -> vssd, vccd -> vssdG vssio
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**NOTE:**
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Type (4) crosses domains, so that the local VCCD has a diode to the
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local VSSD and also to the global VSSD. **BUT:** Although vccd goes all the way
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around the chip in the form of vcchib, vssd does not, which makes the SRC2
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connection effectively unreachable in this configuration, so better to just
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change it to vssd1 and vssd2 for the respective domains.
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New overlay types created:
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==========================
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1. sky130_ef_io__vddio_hvc_clamped_pad: sky130_ef_io__vddio_hvc_pad + overlay (1)
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2. sky130_ef_io__vssio_hvc_clamped_pad: sky130_ef_io__vssio_hvc_pad + overlay (1)
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3. sky130_ef_io__vdda_hvc_clamped_pad: sky130_ef_io__vdda_hvc_pad + overlay (2)
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4. sky130_ef_io__vssa_hvc_clamped_pad: sky130_ef_io__vssa_hvc_pad + overlay (2)
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5. sky130_ef_io__vccd_lvc_clamped_pad: sky130_ef_io__vccd_lvc_pad + overlay (3)
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6. sky130_ef_io__vssd_lvc_clamped_pad: sky130_ef_io__vssd_lvc_pad + overlay (3)
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7. sky130_ef_io__vccd_lvc_clamped2_pad: sky130_ef_io__vccd_lvc_pad + overlay (4)
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8. sky130_ef_io__vssd_lvc_clamped2_pad: sky130_ef_io__vssd_lvc_pad + overlay (4)
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9. sky130_ef_io__vccd_lvc_clamped3_pad: sky130_ef_io__vccd_lvc_pad + overlay (4)
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10. sky130_ef_io__vssd_lvc_clamped3_pad: sky130_ef_io__vssd_lvc_pad + overlay (4)
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**NOTE:**
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The ``clamped3`` pads correspond to a change in the Caravel design for MPW-2,
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in which the vccd/vssd domain has continuous supply rings around the chip
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periphery. The pad connection of these two pads does not connect to the padframe
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power rings, but connects to a separate set of power rails in the chip core.
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